How long will this plush hybrid last before it sags?

The spring core is built to last, scoring 7.1/10 overall for durability. It uses 1000 pocketed coils of thick 13.75-gauge tempered steel that resists sag and fatigue far longer than budget wire. The comfort layers are CertiPUR-US certified high-density foam, which holds up better than cheap foam but is where body impressions gradually form on any foam-topped bed. Made in Ontario with a 10-year warranty. A protector and head-to-foot rotation help extend its life.