The thickness of your air mattress

An air mattress provides a gentler and more consistent sleep surface, so an air mattress bed is often a good choice if you wake up with back or neck pain. Make sure the air mattresses you consider buying are sufficiently “deep” that you don't “bottom out”. Four inches in depth is probably about the thinnest you can get away with, depending on your body weight and the amount of “give” you want in an adjustable air mattress. A thicker mattress—say, about seven inches—will give you plenty of leeway if you want a softer mattress.