A too-firm mattress causes shoulder and hip pain for side sleepers and sometimes lower back pain for everyone. Before assuming you bought wrong, give the mattress 30 nights to break in — most foam mattresses soften 5–15% in the first month as the foam cells fully expand.
STEP 1: BREAK IT IN PROPERLY. Sleep on it nightly for 30 days. Walk on it gently with bare feet for 5 minutes daily (foam-only mattresses). Keep room temp at 68–72°F — cold rooms make foam significantly firmer.
STEP 2: ADD A MATTRESS TOPPER (BEST FIX). A 2–3" topper transforms feel without buying a new mattress. (a) Memory foam topper ($120–$300) — most contouring, runs hot. (b) Latex topper ($200–$500) — durable, cool, responsive. (c) Down/feather topper ($80–$200) — soft and luxurious but compresses fast and isn't allergy-friendly. (d) Wool topper ($300–$600) — moderate softening, temperature regulating, naturally hypoallergenic. Toppers are the highest-impact, lowest-cost fix.
STEP 3: CHECK YOUR FOUNDATION. A solid platform makes any mattress feel firmer than slats do. Slats with wider gaps (4–6") allow more give. Adding a 1" bunkie board on a sprung foundation can add subtle softness; removing a too-rigid plywood layer can do the same.
STEP 4: WARM IT UP. All foam softens with body heat — heated mattress pads ($50–$100) preheat the surface. Set 30 minutes before bed, turn off when you climb in. Especially helpful in cold bedrooms.
STEP 5: ROTATE FREQUENTLY. Rotating 180° every 2 weeks during the first 2 months accelerates break-in evenly across the surface.
WHEN TO RETURN INSTEAD. If you bought from a brand with a sleep trial (most online brands offer 100+ nights), use it. Buying a $200 topper to fix a $1,200 mattress is throwing good money after bad if free return is available. Trial-period returns: Saatva (365 nights), DreamCloud (365), Nectar (365), Helix (100), Tempur-Pedic (90).
FIRMNESS BY SLEEP STYLE — TARGET. Side sleepers: 4–6/10. Back sleepers: 6–7/10. Stomach sleepers: 7–8/10. Heavy sleepers (230+ lbs): add 1 point of firmness. If your mattress is more than 2 points off your target, a topper is a band-aid; return and rebuy.
WHAT NOT TO DO. Don't store the mattress folded or compressed to "soften" it — permanent damage. Don't soak it in water. Don't walk on it aggressively (cracks foam internals).