Here are a few more tips for buying a sofa.
Head to the stores. Go and sit on everything. You may find that things you didn't like initially may actually work better for you than the sofa you had in your mind. You can get some great advice from skilled professionals to help you make the best decisions. We had many clients who came in and tried sofas several times before they made a decision. Don't feel bad about taking your time! Try a wide variety of options.
Be aware of cushion filling and frame quality. This is where you have to read the fine print. But most importantly I would say that your two most important concerns with filling are your comfort and durability. There are some people who love down and some people who love firm foam. Find out which one you are.
Expect a hardwood frame and try to get a sense of the sturdiness of the piece.
Carefully inspect the upholstery work. See how the fabric fits the frame, check seams. Lift up the cushions, look at the seams, see how the skirt sits. Even online I've been able to detect seams that look really awful when I zoom in. That speaks volumes to me about the quality of a piece.
Anticipate that you will probably get what you pay for. Sofas are big purchases. If you buy a sofa for less than $500 don't anticipate it's going to last you more than 6-7 years at most. You may get away with just getting new filling for the seat cushions after a few years. If you're like me you may want to change out your sofas more often anyway.
But if you expect to have the same sofa for 20 years, anticipate what it costs to invest in a piece of that quality. The more you spend the more you should get. Higher end sofas generally come with significant quality guarantees, make sure you protect your purchase by knowing what is covered and then care for your sofa cushions by rotating them around, giving them a good shake out, cleaning soils in fabric that might deteriorate the fibers.
Don't let someone talk you into paying more for something you don't really like sitting on. Don't be dazzled by a sales pitch. Know what you like and invest in a piece that will meet your needs. You can definitely find a great sofa that will work for you, not matter your budget.