Other major purchases such as diamond rings, Persian carpets and original works of art have their finer points on display for all the world to see all the time. But with sofas, the quality lies far below the surface, down in the padding, the springs and the frame. The external appearance only tells a small part of the story.

To help you make the right choice, we've assembled a few questions to ask, along with some things to think for each one.

Who's the sofa for?

If you have children, stain resistant fabrics should be top of mind. If you have toddlers, you may want to stay away from loose cushions because they'll end up in a pile in front of the television or as fodder for a fight between siblings. Teens like to stretch out. So do adults with children as they call asleep watching TV or reading a bedtime story. If you're a single adult, you want to think about the friends you entertain and how you entertain them. If you have an elderly person in the home, you may want to sacrifice some comfort for ease of egress. Firmer cushions can help an older person get in and out of the sofa without assistance. Defining your needs will not only determine the type of sofa you want, but the size and arrangement. How will it be used?

If you're going to be watching your favorite shows on the boob tube you want the minimum length to be 5 ? to 6 feet so you can stretch out. If you don't have small kids who will take the pillows to the four corners of the world, you may want to consider pillow back . They come in handy when you want to lie down. If you're doing a lot of entertaining, you want a sofa that has a more tailored, formal look to it. When it comes to choosing the right arms, squares are more contemporary or modern and discourage people from sitting on them at parties, which reduces wear and tear. If you plan on lying on the sofa, you'll want rounder corners. Even with a pillow, the squared edges can get uncomfortable.

Where is the sofa going?

Living room furnishings tend to be more formal looking than those in a family room or home theater. As such, they have a tighter look to them, the have a more luxurious feel to them and they can have imposing style. They are meant to be the centerpiece of the room. You may even want to consider a sectional for the living room. For the family room or home theater, comfort is more important than style. You can go with something that is more overstuffed and casual. You want the piece in these rooms to be welcoming, since long hours are often spent on them.

When are you using the sofa?

This seems like a strange question. But the time of day helps determine what kind of fabric you want to use. If the sofa is for use during the daytime, consider buying a sofa that has brighter, easy to maintain fabric. If you're going to be entertaining primarily in the evening, you can go with something a little more exotic, such as mohair velvet, silk or damask. If you have guests who occasionally stay the night, you may want to consider buying a sofa that can accommodate an adult sleeper.

It's what's on the inside, really!

1. The frame Think of the frame as being the bones of the sofa. Like your own bones, you want the frame to be strong. Kiln dried hardwood that is free of knots is the sign of mid- to high-end furniture. Lower end . are usually constructed with laminates, metal and plastic. Glued dowels are preferable to nails or screws, which become loose over time.

2. Under the hood on higher quality sofas, upholsterers attach the heavy-duty seat springs individually to the jute webbing using clips. They then hand tie them to one another using an eight-way tie. Lower quality sofas use pre-fab coils, which can still be good. Avoid zigzag springs entirely. They won't hold up over time.

3. The stuffing down wrapped, high-density foam is the best out there. Make sure you ask for the down-to-foam ratio though before you buy a sofa. The government allows for a 15% margin of error on this, so factor that into your calculations of how much is really foam and how much is down. And 80/20 mix may only be 5% wrapped down.

4. The little things that make a difference Quality cushions are lined. If yours aren't you may not be getting what you're paying for. Open a cushion and see if it's lined. This helps keep the feathers from poking through and reduces stress on the exterior fabric.

5. It's a match now, the final indicator. Look at the fabric. If it has a pattern on it and is high quality, the patterns will match from one place to another. If they don't you may be buying a less expensive sofa with a more expensive price tag.

Finally, sit on the sofa, lie on it, relax, lean forward, and sink back. Does it feel comfortable to you? Once you sofa has passed the top five tests and is comfortable to boot, you're ready to buy your sofa in complete confidence.