I had a 2005 Jeep Liberty Limited (with diesel engine) that had one of the earliest versions of TPMS. It also had the fancy onboard computer system so it showed which tire was low. It also alerted to the spare. Now, with a 2010 Tacoma, it only alerts with a dash light for the 4 main tires. I've reached the point where the batteries in one of the sensors has died, and the light is on all the time. I just ignore it and will not be replacing the sensors (just got new tires a couple of years ago). I've been driving since 1960 and always maintained my tire pressures with regular checks. I have no need for an idiot light to tell me to check, and the only flat I've ever had to replace on the road was a trailer tire that just disintegrated.
 

I used to check mine once a week then I just filled them once a month whenever I got gas.
My last car had indirect sensors so that's why I checked once a week. My current car has direct sensors and the rears keep losing air (they're new!). My car seems to settle at 31 front and 38 rear when the door placard calls for 41 rear.
No spare since I have runflats.

quote:

Originally posted by henryaz:
 <snip> I've reached the point where the batteries in one of the sensors has died, and the light is on all the time.<snip>

The TPMS of my 2018 Hyundai Sonata Limited doesn’t produce a reading for the four tires until I’ve driven for a quarter mile or so. I’m suspecting that an induction coil in each wheel charges a capacitor as it passes a permanent magnet mounted somewhere to power the TPMS (rather than a battery). Does anyone know if my guess might be correct?