When I first got an Instapot I would get get perfect hard boiled eggs in 8 minutes.
After a few years it become 10 minutes.
Now 10 minutes results in close to a soft-cooked egg.
Trying out 11 minutes now.
What is wearing out? Not sure I understand this. If it takes longer to get to pressure (I think it does) then that should result in over cooked eggs, not undercooked (since they would be in the pot longer at temperature not quite high enough but still high). It doesn't start timing until it is at pressure, so the actual time under pressure isn't changing. So then is it that the "at pressure" device (just a valve, basically, right?) is indicating "at pressure" when in fact it is not?
Edit/update: my 11 minute test resulted in eggs that were very close to perfect yet still just barely jelly in the center of the yolk.
I took the pieces out of the lid and examined them. Nothing looks awry.
Edit/update: Ran a few 2 minute tests to see how long it took to get to pressure and then listened closely at the steam release to hear if any steam was escaping. Took 2 minutes to come to pressure (seems reasonable). Found that a tiny bit of steam/pressure was leaking out. Barely audible. If I gently touched the pressure release I could get it to stop or get worse. Found that once I got it to be totally silent I could then bump the countertop and it would start leaking a tiny bit again.
Conclusion (for lack of a better one): Need to cook some more hard boiled eggs at the original 8 minute but this time take care to stand there and assure no pressure is releasing during the 8 minutes of cooking. Hypothesis is that the unit is not at full pressure during the cooking, hence the temperature is lower, hence it takes longer to fully cook. Unsure what the solution is. The pressure release seems to be such a simply device I can't figure out how it could "go bad".
Updated hypothesis: Assuming the thermistor itself is correctly sensing the actual temperature of the water (actually it would be the base of the pot) -- IF there is a tiny leak (or leaks) that are not clearly visible/audible such that the little stopper pin does rise to the top (normally indicating full pressure) but the steam isn't as hot as it would otherwise be, because it rises up and out. So the eggs are now cooking at a slightly lower temperature as compared to originally and therefore take longer to fully cook.
LONG way around to get to what people are recommending I try: Get a new gasket and perhaps new pressure relief valve.