First, it is important to always consider the addition of a new box spring when purchasing a new mattress. The box spring significantly increases the life expectancy of the mattress. By using a new mattress on old box springs, you could decrease the life of your mattress from 10 years to 3 or 4 years. Therefore, it makes financial sense to protect your investment in a new mattress by purchasing a new box spring. Next, it is important that you choose a mattress with proper support.
Support is determined by the number and the gauge of the coils within the core of the mattress.
Typically, there are between 300 and 700 coils in a mattress. Therefore, if you are looking for a very firm mattress, then you should consider only the mattresses with high coil counts. Finally, you must consider the type upholstery that fits your needs. The upholstery on top of the mattress is most important for the basic comfort of the body. If you like to feel like you are sleeping on a feather bed while actually getting great support, then you should consider a pillow top mattress.