It doesn’t look right
The most obvious sign that you need a new mattress is that it doesn’t really look like a mattress anymore. Rick Maynard, spokesperson for Stearns & Foster, recommends looking for visual cues when changing your sheets. If it’s uneven or sagging in certain areas, that’s a pretty good indication that it is no longer providing the support you need when you sleep and that it’s time for a new mattress. These are the things you should know when shopping for a new mattress.
Your bed shouldn’t be loud, even when you’re tossing and turning. If you hear grinding metal or can feel displaced springs, it means that the foundation of your mattress isn’t strong anymore.