Furniture shopping is about more than just style; there are so many elements that go into getting the right fit for you and your home. These five are the essentials. Don't leave the store without doing this stuff.
Sit on it
Duh. But sit on it mindfully! You're looking for not only comfort, but also how this piece fits your body. Does the seat accommodate the length of your thighs? Do your feet rest comfortably on the floor? Is the arm rest at the right height for your own arm? Little scale problems might not seem like a big deal, but will add up to an uncomfortable experience after a few hours of lounging. Make sure everything is perfect.
If this is a secondhand find, you are looking for manufacture's markings to tell you exactly what you've found. If you're buying from a store, check to see how the piece is put together. If you can, look at joints, fabric fastenings and other signs of quality. You can be sure that if the finishes look shoddy, the construction inside isn't any better.
In most cases, the weight of your purchase signifies its quality. If it's lighter than you expect, it could be a sign that the frame isn't as solid as it could be. If you're in the market for a cheapie, short-term piece that you can easily move around every other week when you rearrange your living room, this may be just fine with you, but make sure it's priced accordingly.
Examine the fabric/finish
This is the color/texture/pattern you will see every day so make sure it's up to par. Think about both the feel of the fabric or wood and also about what it will take to care for this finish. Maintenance is a huge part of keeping your piece looking good, so decide if you have the patience to polish that glossy wooden table every week or if you'd be better served by a more rustic (and low maintenance) choice.
Measure it twice
Pull out your trusty measuring tape (the one you have with you, right?) and get all the measurements. Then do it again for good luck. Now make sure that you have the space for this thing (and plenty of wiggle room). Did the Craigslist seller tell you the numbers already? Check them yourself. Nothing is worse than arriving home with a new piece only to discover it doesn't fit in your space (or through your door). Better safe than sorry.
What else do you always do with your potential new furniture?