How to fix your mattress if it's dipping on just one side — and why it happens

A person places their hand on one side of their white mattress to check for signs of dipping and sagging.

Over time, you may notice that your mattress is starting to dip on one side only. While some sagging and dipping is bound to occur as your mattress gets older, a dip on just one side is easy to prevent. 

Here we break down five common reasons why a mattress dips on one side only, along with how to fix those dips – and even prevent them from occurring in the first place. Many of these fixes are quick and free too, so you don't have to invest lots of time or money to solve your problem.