Summarize:

If you haven’t purchased a mattress in a while, it’s good to see what options are available before going to a store.  Check prices online to see what you feel is reasonable based on what is being offered. Mattress brands are often coming out with new styles of mattresses including ones that offer adjustable firmness levels and temperatures. Decide how high-tech you want your mattress to be, as some of these may only be available at specialty stores or online. Look up what special features may be offered by each mattress brand including a trial period or money-back guarantee. If desired, you can print this information to bring to the store with you. Although this is difficult to determine without first testing mattresses, a few physical factors can help direct your decision.  If you have back problems, consider a medium-firm to firm mattress choice. These are best for supporting your lower back and reducing back pain. Pillow-top mattresses are best for people who aren’t too light, as they won’t have enough weight to suppress the top and the springs to a point that it makes a difference in comfort. Larger people typically find pillow-top mattresses more comfortable for this reason. Ignore the spring count that is given as proof for a mattress’ supposed quality and firmness or softness. Studies have shown that the number of springs doesn’t actually affect how comfortable the mattress is. Nothing is worse than finding and purchasing your perfect mattress, just to realize you can’t fit it in your house. Check your space availability in your bedroom, and then decide on a size of mattress to fit.  Twin mattresses are the smallest size, and measure on average 39”/75”. The next largest size after a twin mattress is a full or double mattress, which measures at 54”/75”. The queen sized mattress is the most commonly purchased by couples for its size and relative price. It measures at 60”/80”. King size bed is the largest standard sized mattress available. It is 76”/80”. Some mattress brands and stores offer an extra large bed called the California king, which measures at 72”/84”.  Be sure the mattress size you intend to purchase not only fits inside your bedroom, but also through all doors used to enter the room. Typically, specialty mattress stores will have more informed salespeople and information on mattresses than a generic furniture store. Be sure that where you choose to buy has a good reputation and helpful employees.
Visit mattress websites to see what’s offered. Decide on a level of firmness. Measure the space you plan to put the bed. Find a store(s) to shop at.