20 Costco Items Shoppers Regret Buying—And What to Check Before You Buy

Costco has plenty of bargains, but not every purchase becomes a keeper. From costly appliances to prepared meals, these 20 items have sparked return reports and buyer complaints. Here’s what to check before they land in your cart.

Editor’s note: This list combines shopper-reported returns, product complaints, and Costco employee accounts. It is an editorial countdown, not an official ranking of Costco’s most-returned merchandise. Individual experiences vary.

20. Large Containers of Spring Mix and Baby Spinach

Those oversized containers of fresh greens look like a bargain, but they can become expensive compost surprisingly quickly.

• What shoppers noticed: Returns-counter employees have described customers bringing back greens that turned slimy, wilted, or discolored sooner than expected. Large packages also create problems for households that cannot finish everything in time.
• Before you buy: Look for condensation, damaged leaves, and discoloration. Check the date and consider how many salads or meals you can realistically prepare.
• Our take: Great for households that eat greens daily. Smaller packages may be a better value if you regularly throw half the container away.

19. Costco Whole Watermelons

Few grocery disappointments are worse than cutting into a beautiful watermelon and discovering the inside is soft, mushy, or already deteriorating.

• What shoppers noticed: Recent buyers described disappointing watermelons, including fruit that broke down unexpectedly soon after purchase. Older employee accounts also identify watermelons as a recurring produce-return item.
• Before you buy: Check for cracks, leaking juice, unusually soft spots, and other signs of damage. Avoid buying more than you can refrigerate and eat promptly.
• Our take: Watermelons are naturally unpredictable, but a bargain loses its appeal when the fruit is inedible. Inspect carefully rather than assuming every melon in the display is equally fresh.

18. Kirkland Signature Bakery Muffins — Newer Eight-Packs

Costco’s famous oversized muffins built a loyal following, which explains why the switch to smaller versions caused so much frustration.

• What shoppers noticed: Some longtime fans complained that the newer muffins tasted drier, denser, or less flavorful. The move from two six-packs of jumbo muffins to newer eight-count packages also changed the value calculation.
• Before you buy: Don’t assume the current muffins taste or feel like the old versions. Check the package size and choose flavors your household already enjoys.
• Our take: The smaller portions are convenient for some families, but longtime jumbo-muffin fans may find the newer versions disappointing.

17. Kirkland Signature Protein Bars

The nutritional numbers are appealing, but taste and texture are where these bulk boxes divide shoppers.

• What shoppers noticed: Some customers criticized the Chocolate Brownie and Chocolate Chip Cookie Dough varieties for being unusually firm, chewy, or unpleasantly dense. Others love them for the protein and fiber.
• Before you buy: If you dislike dense protein bars, think carefully before committing to a large box. Flavors can have noticeably different textures.
• Our take: A practical protein snack for people who enjoy the texture, but not necessarily a satisfying replacement for a regular chocolate snack bar.

16. Kirkland Signature Pesto Pasta Salad

This prepared deli dish looks like an easy dinner, with spiral pasta, basil pesto, mozzarella pearls, roasted tomatoes, and arugula.

• What shoppers noticed: Complaints focused on bland seasoning, an overwhelming pesto flavor, and occasional pieces of pasta that felt too firm. One customer reported returning the salad rather than keeping an expensive meal they didn’t enjoy.
• Before you buy: Check the total container price, not just the price per pound. Some shoppers were surprised to find that the large trays cost around $20 or more.
• Our take: If you like bold, fresh pesto, you may enjoy it. Otherwise, a smaller homemade batch gives you more control over the seasoning and portion size.

15. Bento Onigiri Rice Balls — Six-Pack

These individually wrapped Japanese-style rice balls attracted attention for their convenient format and three fillings: Teriyaki Salmon, Spicy Crab, and Tuna Mayo.

• What shoppers noticed: Some buyers complained that the rice was hard or gummy. One customer returned the six-pack after finding very little tuna filling in the first rice ball, although other reviewers praised the filling portions.
• Before you buy: The six-pack was spotted for $11.99 in September 2026. Refrigerated rice has a different texture from freshly prepared onigiri, so adjust your expectations.
• Our take: Convenient for an easy lunch, but shoppers who prioritize soft rice and freshly prepared fillings may prefer an Asian grocery or Japanese market.

14. Costco Prepared Nigiri Sushi

Ready-to-eat sushi sounds like a convenient warehouse find, but the rice can make or break the experience.

• What shoppers noticed: An August customer reported returning a nigiri purchase because the rice was extremely hard. Other shoppers have raised similar texture concerns about some refrigerated sushi products.
• Before you buy: Look at the preparation and packaging dates, and remember that chilled rice may become firm. Don’t assume the quality matches sushi prepared to order.
• Our take: This is a product to approach cautiously if fresh, soft sushi rice is especially important to you. Complaints about this nigiri should not be confused with reviews of Costco’s other sushi and poke products.

13. Above-Ground Pools, Swing Sets, and Outdoor Playsets

Costco’s seasonal outdoor equipment can look like an excellent deal, especially when comparable products cost substantially more elsewhere.

• What shoppers noticed: Employees have described seeing pools, playsets, and other bulky outdoor equipment returned. Reported reasons include defects and dissatisfaction, although the circumstances of individual returns are not always clear.
• Before you buy: Check assembled dimensions, ground requirements, maintenance needs, replacement-part availability, and storage arrangements.
• Our take: These purchases work best when you’ve planned where they’ll go and how you’ll maintain them. The biggest mistake is buying a large seasonal item before understanding the work involved.

12. Plush Shag Area Rugs

A thick, fluffy rug can make a living room look more inviting. Keeping it clean is another story.

• What shoppers noticed: In an October 2026 discussion, one customer reported returning a $500 shag rug after six months because children’s snacks and crumbs became trapped deep in the fibers.
• Before you buy: Consider pile height, vacuum compatibility, and whether the rug will sit in a busy room with children or pets.
• Our take: Plush rugs are attractive in low-traffic spaces. For family rooms, a low-pile washable rug may be the more practical purchase.

11. Expandable and Kink-Resistant Garden Hoses

Lightweight hoses promise easy handling, compact storage, and fewer frustrating tangles. Some shoppers found that convenience came with durability concerns.

• What shoppers noticed: Buyers described leaks, failed fittings, and expandable hoses deteriorating after relatively short periods. Some reported returning multiple hoses after experiencing similar problems.
• Before you buy: Pay attention to fitting materials, pressure ratings, sunlight exposure, and the manufacturer’s warranty. A hose advertised as kink-resistant isn’t necessarily kink-proof.
• Our take: Choose a durable hose that fits your daily needs rather than buying solely for the lightweight design or compact storage.

10. Portable Air Conditioners

When temperatures rise, portable air conditioners seem like an easy solution for rooms that need extra cooling.

• What shoppers noticed: Costco employee accounts identify portable A/C units among recurring returns. Some customers complained that the cooling performance did not meet expectations.
• Before you buy: Match the unit’s rated cooling capacity to the room, consider sun exposure and insulation, and check the exhaust-hose requirements. Noise matters, too, especially in bedrooms.
• Our take: Portable units make sense where window or permanent systems aren’t practical. If you can install a suitable window unit, comparing its performance and efficiency may save disappointment.

9. Shark Hair Dryers

A premium hair dryer is supposed to make styling easier while lasting long enough to justify its price.

• What shoppers noticed: In October 2026, a Costco Canada member reported returning a Shark hair dryer after it stopped working. The commenter believed the product had been owned for more than a year but did not identify the exact model.
• Before you buy: Compare the warranty, weight, attachments, replacement-part availability, and real-world reliability feedback for the specific model.
• Our take: One failure does not establish a widespread Shark problem. However, spending hundreds on a styling tool makes warranty coverage and long-term durability especially important.

8. Ninja DualBrew and Other Multifunction Coffee Makers

A machine that brews both single servings and full pots sounds ideal for a busy kitchen, but extra functionality also means more components to manage.

• What shoppers noticed: A Ninja DualBrew customer described coffee spilling while pouring, while another reported returning the same type of machine because of problems involving single-serve brewing and grounds. A separate October 2026 customer reported a refund after an unspecified Ninja coffee maker failed.
• Before you buy: Decide whether you genuinely need multiple brewing formats. Compare how easy the machine is to clean, refill, and descale.
• Our take: Multifunction brewers suit households with different coffee preferences. If you only make one type of coffee, a simpler machine may offer better everyday value.

7. Costco Clothing — Especially Pants, Jackets, and Seasonal Apparel

This is one of the most interesting return categories because a returned garment doesn’t necessarily mean anything is wrong with its quality.

• What shoppers noticed: Employees have identified clothing as a high-volume return category, largely because Costco doesn’t have traditional fitting rooms. Customers often discover at home that their chosen size or cut doesn’t fit.
• Before you buy: Check the brand’s measurements, fabric composition, stretch, and washing instructions. Don’t assume two brands carrying the same size will fit identically.
• Our take: Costco clothing can still be an excellent bargain. Just be selective about unfamiliar brands, especially when buying several pieces at once.

6. Mattresses — Especially Unfamiliar Memory Foam and Hybrid Models

Mattresses are among the most expensive purchases shoppers make without knowing exactly how they’ll feel after several nights.

• What shoppers noticed: Return accounts describe mattresses that felt too firm, became uncomfortable, or developed impressions sooner than expected. Costco employees have also identified mattresses as a recurring return category.
• Before you buy: Compare firmness, construction, support, motion isolation, mattress height, and long-term owner experiences. Consider your sleeping position rather than relying on a model’s popularity.
• Our take: Costco can offer strong mattress value, but comfort is highly personal. Research the exact model and avoid assuming a mattress labeled medium-firm will suit everyone.

5. Costco Sofas and Sectionals — Including Coddle Furniture

Furniture can be one of Costco’s biggest savings opportunities, but buying a sectional without spending time on it creates obvious risks.

• What shoppers noticed: Complaints have involved uncomfortable upholstery, firmness that didn’t match expectations, delivery issues, and defects. A September 2026 complaint involving a Coddle Bumper Sectional described delivery delays and a defective sofa; Costco subsequently coordinated a return pickup.
• Before you buy: Check the assembled dimensions, seat depth, fabric texture, cushion construction, and delivery arrangement. Read the exact model’s reviews rather than judging by appearance.
• Our take: A beautiful sectional isn’t a bargain if nobody enjoys sitting on it. For large online furniture purchases, understand the delivery and return arrangements before ordering.

4. Shark Matrix Robot Vacuums

The promise of automated cleaning makes robot vacuums tempting, particularly for busy homes with pets and children.

• What shoppers noticed: A September 2026 buyer reported returning a Shark Matrix after just one week because it was frustrating to use. Other customers reported issues involving cleaning performance or mechanical reliability, although many owners also have positive experiences.
• Before you buy: Look closely at navigation, obstacle avoidance, floor transitions, app controls, noise, and how easily the robot handles hair and debris.
• Our take: A robot vacuum should reduce chores, not create new ones. Houses with toys, cords, clutter, or difficult floor transitions may require a more capable model.

3. Roborock QX Revo Robot Vacuum and Mop

Roborock’s vacuum-and-mop systems receive considerable praise, but their advanced features also create maintenance requirements that basic vacuums don’t have.

• What shoppers noticed: A September 2026 buyer reported returning a QX Revo after about five months when its mopping system stopped functioning and troubleshooting didn’t resolve the issue. Other owners have described separate mechanical problems, while many praise the cleaning performance.
• Before you buy: Understand how to maintain the mop system, clean the dock, and use manufacturer-approved cleaning solutions. Check your exact model’s warranty and replacement-part options.
• Our take: A good choice for shoppers who value automated mopping and will keep up with maintenance. Buyers expecting a completely hands-off system should think carefully before spending several hundred dollars.

2. Keurig Single-Serve Coffee Makers — Including K-Supreme Models

Keurig coffee makers are convenient, familiar, and widely popular. They’re also among the most frequently mentioned appliances in historical Costco employee return discussions.

• What shoppers noticed: Former returns employees described seeing Keurig machines repeatedly, including smaller models. Owners reported machines failing, experiencing brewing problems, or becoming unusable after maintenance cycles. Other customers said their machines lasted for years without trouble.
• Before you buy: Review feedback for the exact model, its descaling procedure, reservoir design, and warranty. Consider whether you want the convenience and ongoing expense of single-use pods.
• Our take: Keurig can still be convenient for occasional single-cup brewing. If reliability, repairability, or inexpensive daily coffee matters most, compare simpler drip brewers before choosing one.

1. Dyson Cordless Vacuums — Particularly the V15

Dyson takes the top spot in our editorial countdown because it combines recurring employee return reports with identifiable, recent complaints about expensive cordless models.

• What shoppers noticed: Some Costco employees have named Dyson among the most common appliances at their local return counters. In July 2026, V15 owners discussed reliability issues, and one customer reported returning three V15 units after repeated problems. Other Dyson owners reported years of satisfactory use.
• Before you buy: Pay attention to battery life, trigger or switch operation, replacement-part costs, filter maintenance, weight, and the warranty on the exact model. Test it thoroughly while it is new.
• Our take: Dyson can deliver impressive cleaning performance, but the premium price deserves premium scrutiny. If long-term repairability matters more than cordless convenience, compare alternatives before spending the money.