How durable is a 15.5-inch pillow-top like this?

Built to hold its feel, with a durability score of 8.0. This pillow top runs high-density comfort foam, founder-rated in the firm-and-dense range, over 1000 pocketed coils of heavy 13.75-gauge steel, which resists sagging far longer than thinner wire common at this height. Denser foam and heavier coils slow the body impressions that form first in the comfort layer. It is built in Ontario and backed by a 10-year warranty; rotating it periodically helps it wear evenly.