Answers, built from engineering.
Plain explanations of how mattresses, pillows, and sleep structure actually work — written by the people who build them.
Why mattresses sag in the middle.
Sagging isn't material wear — it's structural failure. The center third carries most of body weight, and most mattresses are built uniformly edge to edge.
Browse by question type.
Understanding Mattresses.
Why mattresses soften, why "firm" doesn't mean supportive, and what actually wears out. The mechanics behind it.
Buying Better.
Decision help before you buy. What to look at, what to ignore, and how to read marketing claims at face value.
Sleeping Better.
What your mattress is doing now — dips, morning soreness, sagging, uneven support. What the signs mean and what to check.
All articles.
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What pillow height suits your sleeping position?
The right pillow height depends on the gap between your head and the mattress in your usual position. Side sleepers need more loft to fill the shoulder gap, back sleepers a moderate height, and stomach sleepers the least. The aim across all three is the same: keep your head supported and roughly level.Read →N°01 -
Loose-fill vs fill-free adjustable pillows.
Both let you change a pillow's height. Loose-fill adjustable pillows add or remove shredded foam or down — moldable and fine-tunable, but the fill shifts and needs re-fluffing. Fill-free adjustable pillows use a core plus a removable insert, so the set height holds. The honest trade-off is control versus consistency.Read →N°02 -
Why does my pillow go flat?
Going flat is loft loss — the height under your head drops. Loose fill compresses and migrates to the edges under nightly pressure, and solid foam can soften over time. Re-fluffing redistributes fill temporarily but doesn't rebuild it. How long a pillow keeps its height depends mostly on how it's built.Read →N°03
The technology behind these answers.
Manchot's StasisLayer® System is the structural reasoning that informs every article here.
Engineering, when explained clearly, doesn't need to sell itself.