With daily use, HIMARI 日葵 and SORA 宙 gradually settle. How long each remains comfortable depends on the sleeper, frequency of use, base and care routine. Consider replacement if persistent flattening, lumps or loss of cushioning make it uncomfortable. Air and check it regularly, and contact us if you are unsure about its condition.
Why three to four years
The filling gradually becomes more compact with use. Airing, turning and a firm, level base help distribute settling. Frequency of use, body weight and care all affect service life.
The simplest test: measure it
After airing, check for persistent flattening, lumps or areas where you can feel the base through the bedding. If the cushioning no longer feels comfortable, contact us for advice or consider replacement.
When comparing floor mattresses, consider construction, filling and intended use as well as thickness. The initial thickness of another model does not determine when it should be replaced.
How to make the loft last
- Fold it away each morning so the underside and the floor can dry.
- Turn it over and rotate it head to foot regularly, so the same areas are not always under pressure.
- Air both sides every one to two weeks in dry weather.
- Use it on a firm, level base; a soft or uneven surface underneath lets it sag.
Heavier sleepers
We do not publish a tested weight limit for either model. Body weight affects how bedding feels and settles, so use a firm, level base and turn and rotate the shikibuton regularly. SORA 宙 offers fuller cushioning with a balanced medium feel; HIMARI 日葵 has a firmer feel.