Visit a mattress store or department store. Mattress technology changes all the time and, depending on when you purchased your old bedding, there may be a lot of new features to consider.
Try one out. Lie down on a mattress that you think you might like. Be sure to stay there for at least a few minutes and up to 10 minutes to really get a feel for how the mattress suits you. Stretch out and change positions. If you brought your bed pillow, use it. Your spouse, partner or anyone else who regularly sleeps in your bed should also try the mattress to make sure it is comfortable.
Find out how the mattress is made. Does it have coils or is it tempered? If it has coils, the lower the gauge of a coil, the thicker it is and the thicker the coil, the firmer the mattress.
Consider the size of the mattress and foundation, and the size of your bedroom. For a king-sized mattress, you will need a king-sized foundation.
Sleep on it, if you can. Some stores allow customers to try out a mattress for a week or so. If the store offers this service, take it.
Find out the store's delivery and return policies. Will it deliver the mattress for free? How are returns handled if you aren't satisfied? A mattress is a large purchase and you want to make sure you are happy.