When you sit on the edge of a mattress, your weight could really bring the edge down were it not for edge support — the purposeful reinforcement of the perimeter of a mattress. A bed with adequate edge support is less likely to sag, and you are less likely to inadvertently roll off of a bed with good edge support.As if these reasons aren’t enough, a mattress with a reinforced edge is simply easier to get in and out of. This may not be an issue for everyone all the time, but for people who are sick, injured, or infirm, a mattress with a supportive edge can mean the difference between a struggle getting into bed and an easy time getting into bed.