So what are mattresses made of? It’s a pretty short list of materials actually. There are only two types of foam used in beds: plastic foam, or rubber foam, about a half dozen really commonly used coil systems, air or water bladders, and batting materials. That’s all there is.
Once you understand all of these materials, and how they wear, then you can look at any spec sheet, and have a reasonable expectation of how long the bed will be comfortable. As well as what you’ll need to do to maintain it all long as possible.
Whether you’ve chosen pocketed coils (aka encased, coils, or individually wrapped coils), or a linked unit (bonnell, lura-flex, offset coil, continuous coils, etc) you can expect very little wear to the coils over the course of a decade or more. Elements that will impact the continuity of comfort is gauge of the wire and the number of coils. Lighter gauge coils or too few of them, will not be sufficient to handle the weight of an adult in the long term.
Pocketed Coils
Pros: Less motion transfer, better contouring with less foam, fewer pressure points.
Cons: Less even distribution of wear.
Linked Coils
Pros: Very durable, even wear of materials when flipped.
Cons: Requires more materials to hide the feel of the coils, more motion transfer
Special Note:
Foam encasements on coils will wear out faster. It may feel good to sit on the edge at the beginning. But your overall sleeping area shrinks as the foam around the outside compresses. Material wear with different types of coils can vary. If you have a linked coil system, the weight distribution on the batting or foam underneath is very uniform. As the mattress gets flipped and rotated through the years, the mattress will get thinner, but the bed will continue to look and feel flat, and flat=comfortable.
With a pocketed coil unit, there is a pyramiding out of weight underneath the mattress, but it is not totally even. This requires more diligent rotation and flipping to keep the bed looking and feeling flat. The good news is, on a well designed pocketed coil bed, there is not as much need to make the bed thick to hide the feel of the coils (as they do much of the contouring on their own), and therefore, the potential for sagging is much less to begin with.
What kind of mattress did you grow up sleeping on?