At the time I was just focused on why my buddy was having to replace 200 thermostats in ten years. It turned out you could just cut out the battery with a pair of dikes and jumper the leftover positive post to 3v to get basically unlimited lifespan, so he did that instead of replacing the thermostats with new ones. Afaik most are still working fine.

Helping him out is also how I figured out the defrost timer disintegrating gears thing. When you do things at scale, things that seem random in onesies practically scream at you. It made me appreciate the value gathering data…you can find the patterns at lower scales.

The car air vent thing I figured out on my 94 Toyota 4runner. The air vent crossbars that keep the vanes in alignment with each other all failed over a two year period. A minor annoyance, but it makes you feel like you need a new car lol. I popped them out and found that of all of the plastic parts, only the crossbars were exceptionally brittle. Suspiciously, the bars also had what looked like date codes molded into them. None of the other pieces had numbers at all. I just printed new crossbars.

Though interestingly LEDs in various components or even LED strip lighting seem to last for many many years.

Le sigh.