Shopping Tip #1
#1. Always know the return policy.
This is the absolute number one thing to make sure you always know about a store or sale, especially if you shop like I do. I tend to shop alone and buy large quantities of clothes at one time, which makes it difficult (and time consuming) to try everything on in the stores, since most have a dressing room limit between 5 and 8 items at a time. I try to narrow it down as much as possible, then take everything home to try on. As a result, at least some returns are inevitable.
Most "normal" stores have fairly generous return policies, allowing up to 90 days to return items. (During the winter holiday shopping season, they often allow even longer.) Even those that have shorter policies usually allow at least 30 days. Hang on to all your receipts, because you frequently can't get anything other than a direct exchange or store credit without one. (And, if you don't have your receipt for the return, you'll only get back whatever the item is currently selling for, and not necessarily what you paid for it.)
On the other end of the spectrum, most secondhand stores and "As Is" sales don't allow any returns, practicing an "all sales final" policy. (This, of course, also extends to library book sales and yard sales.) This doesn't mean that you shouldn't shop at these stores and sales; you just need to be aware of the situation. When returns aren't possible, you either have to be 100% certain of your purchases before heading up to the register, or you have to be willing to accept some losses if not everything works when you get it home.
Personally, even at no-return stores, I never try on in the store. I've gotten very good at knowing what will fit me without trying it on — if you hold pieces up to you properly, you'll be able to accurately know if they will fit at least 90% of the time. I also know that if I buy something that winds up being too small for me, I have 3 other people (my mom and two sisters) in varying smaller sizes who may fit into the item; if it's too big, I can have it taken in.