How long will this mattress stay supportive?

Durability is solid for a hybrid, scoring 8.4. The comfort layer uses genuine high-density foam at 2.53 lb, well above budget grade and slow to form a body impression, and a firm tight-top surface resists visible dips longer than a plush one. Beneath it, 1250 coils on 13.75-gauge tempered steel spread load so no single spring is overworked. Serta backs it with a 10-year warranty; rotating it occasionally helps it hold its feel.