Check when to replace your mattress.
Mattress life depends far more on construction than on price: innerspring units soften fastest, foam sits in the middle and latex lasts longest. Nightly hours scale that baseline against a reference of eight, and visible sagging cuts the expected life by nearly a third because body impressions are the failure mode that actually affects sleep. Comparing age against the adjusted life gives the years remaining.
Mattress remaining life
Expected life = type baseline x (8 / nightly hours, clamped 0.7-1.3) x 0.7 if sagging; years left = expected life - current age
These figures are estimates based on population-average formulas and are intended for training and recreational planning only. They are not medical advice. Consult a qualified health professional before starting or changing an exercise programme, particularly if you have an existing medical condition.
Every seven to ten years for most types, sooner for innerspring units and later for good latex. Sagging, waking with new aches or sleeping better away from home are the practical signals.
Yes, noticeably for foam and hybrid designs. Rotating every three to six months spreads compression across the surface.
It changes spinal alignment during sleep and is a common contributor to morning back and hip discomfort, which is why sagging weighs heavily in the assessment here.