THE SIGNS. Too firm shows up as pressure rather than ache. Side sleepers feel it at the shoulder and hip — the two points carrying the most load against a surface that will not yield — and often wake with an arm that has gone numb. You toss frequently because no position stays comfortable for long. Your lower back may feel unsupported on your back, because the mattress bridges the lumbar curve instead of filling it. And the bed can feel like it is pushing back rather than holding you up.
BREAK-IN IS REAL BUT LIMITED. New mattresses do soften slightly in the first weeks as the comfort layers relax, and brands build this into their trials. Several go further and require a minimum break-in before you can return at all — Tempur-Pedic asks for 30 nights and Purple for 21. Give it those weeks honestly. But break-in shifts feel by a small amount, not a firmness category. A mattress that feels punishing at week four will still be too firm at month six.
CHECK THE BASE BEFORE YOU BLAME THE MATTRESS. Putting a mattress on the floor or on a solid platform removes every bit of give the base was contributing and can make the whole bed feel harder than the same mattress on a sprung or slatted foundation. If the mattress felt different in the showroom or in a previous bedroom, the base is the variable that changed.
WHAT ACTUALLY SOFTENS A MATTRESS. A soft topper is the fix that works, and this is the one direction where toppers genuinely deliver: 2–3" of memory foam or soft latex over a firm, structurally sound mattress meaningfully changes pressure at the shoulder and hip. Memory foam responds to temperature, so a warmer room softens it. A quilted mattress pad adds a small amount of surface cushioning. And on a side sleeper, a correctly-heighted pillow sometimes solves what feels like a mattress problem, because a firm surface needs a thicker pillow to keep the neck in line.
WHAT DOES NOT WORK. Walking on the mattress or otherwise trying to force it in — you can damage the comfort layers without changing the firmness. Waiting past the trial window in the hope it improves; that is how people end up owning a mattress they cannot return and cannot sleep on. And no warranty covers a mattress being too firm, because comfort is explicitly excluded everywhere.
WHEN TO STOP FIXING AND START SHOPPING. Firm-to-soft is the one direction a topper handles well, so if the mattress is sound, a good topper is often the cheaper and genuinely effective answer. But if you are still inside the trial, return it instead — you get a full-height comfort layer built into the mattress rather than a slab that slides around, and the trial is exactly the mechanism for this problem. Watch the clock: trial windows are counted in nights from delivery and some brands deduct a return fee.