Do pocket-coil hybrids like this sag over time?

A quality pocket-coil hybrid resists sagging when properly supported, and this model is backed by a 10-year warranty that covers sagging beyond the stated tolerance. To protect it, always use a flat, firm, fully supportive base, rotate it periodically if recommended, and avoid an under-supported frame. Normal body impressions can form, but excessive sag is what the warranty addresses.