Which common mattress advice is actually wrong?

Key points

• • Firmer is not automatically better for backs
• • One-sided mattresses should never be flipped
• • Eight years is an average, not a deadline
• • Longer warranties are usually more prorated, not better

Myths about comfort

These send people to the wrong end of the firmness scale.

• • "Firm is better for your back" — medium-firm generally outperforms both extremes
• • "You get used to any mattress" — you adapt to feel, not to poor support
• • "A topper can fix a sagging mattress" — a topper follows the dip underneath it

Myths about care

Two of these actively damage mattresses.

• • "Flip your mattress twice a year" — only if it is genuinely two-sided
• • "Sunning a mattress kills everything in it" — UV does not penetrate the layers, and outdoor humidity can make things worse
• • "Steam cleaning sanitizes a mattress" — it drives moisture into layers that cannot dry

Myths about buying

These are the expensive ones.

• • "Replace every eight years" — replace based on condition and sleep quality
• • "A 25-year warranty means it lasts 25 years" — check the non-prorated period
• • "Expensive means durable" — foam density and coil gauge predict lifespan, not price
• • "You must buy the matching foundation" — you must meet the support requirement, which is different