[samatman]

Biological systems seeks homeostasis on a very deep level. A lot of our brain is devoted to normalizing volume and brightness, for example.

The reason chili enthusiasts need more over time is basically the same as the reason heroin enthusiasts do.

[wizofaus]

But our sensitivity to temperature doesn't decrease with age, if anything the opposite... even if that's more obvious with ambient rather than tactile temperature (which I'd imagine are processed quite differently by our nervous systems).