Ideally, You should replace your mattress every 7-10 years. However, the lifespan of a mattress depends on several factors such as the quality of the mattress, the frequency of use, and how well it has been cared for. A mattress can start to deteriorate and lose its support after several years of use. If a mattress is visibly sagging or has lumps or bumps, it's probably time to replace it.