Why is it that more expensive mattresses = better sleep? My experience is that it's not about the cost of an individual chair, or mattress, or desk, or whateve

Why is it that more expensive mattresses = better sleep? My experience is that it's not about the cost of an individual chair, or mattress, or desk, or whatever. It's about the cost of the process. The ideal mattress for you, today, might only cost a few hundred bucks, but you may have to put half a dozen of those cheap mattresses to the test to find it. And then your needs might change, because people grow older, and you'll need a different cheap mattress. Your needs are going to change from day to day or from year to year. So what you want from furniture that's built to last is: Adjustability (you can change the height, the tension, or the angle without sacrificing structural soundness or necessary rigidity) and/or flexibility (the furniture is suitable for a wide range of postures and uses; a classic example is memory foam, which slowly adjusts itself to you). Not to mention: Portability and resale value, because you'll be auditioning a lot of stuff. Consider desks, for example. At any given moment in my life, including this one, I could take my computer desk and replace it with a strategically stacked pile of cheap cardboard boxes. And, indeed, when I get a crazy new idea for a room arrangement (standing desks!) I tend to prototype it with cardboard boxes. But: The cardboard boxes are risky; they tend to fall apart over time, or fail very suddenly at moments of high stress. They also have poor structural characteristics; typing on a platform built out of cardboard, for example, can be quite unsatisfying, because it is squishy. And most importantly, the cardboard boxes don't adjust well at all. To change the height or position of my monitor or keyboard I have to find other boxes, or take everything apart and restack. Ergonomics is a game of inches. The ability to easily adjust something by an inch one way or the other is very valuable, and you are going to pay for that, either by buying something adjustable, or by auditioning two or three versions of everything, or by spending a lot of time jury-rigging things.