Read the return terms first
Check the policy for the exact item, seller, size, and delivery location before ordering. Note the return deadline, any fees, and the condition required. A return policy on the brand's own website may differ from an Amazon seller's terms. Keep packaging and tags as required. If the listing does not explain whether an indoor try-on is allowed, ask before treating that as permission.
Check both feet while standing
Put on your usual socks and both slippers. Settle your heels naturally, without deliberately holding your feet farther back. Look at your longest toes and notice the sides and tops of the toe area. With slides, check whether either end of your foot rests on a raised rim. With closed styles, notice any seam or lining that occupies the space you need.
Walk only as the policy permits
On an allowed clean indoor surface, take a few ordinary steps and turns. Check whether the foot moves forward, whether the heel slips more than you want, and whether you keep adjusting the upper. Evaluate the cushion separately. Do not take a new pair outside or remove required tags before you have decided to keep it. A short try-on cannot establish long-term durability.
Write a decision you can use next time
Record the model, size, width, socks, toe clearance, heel movement, and underfoot impression. Use plain descriptions such as front seam touches my second toe or heel shifts after a turn. If you return the pair, retain these notes while following the seller's process. They are more helpful for the next search than a general label such as uncomfortable. When a slipper solves one issue and creates another, use the new issue to choose the next shape rather than repeatedly increasing the size.