When I was shopping for TPMS I looked for unit with an "Early Warning System" that alarms when the tire first starts to loose air.
Some systems only warn after you have lost lots of air.
Assume your cold inflation pressure is 65psi. This means your hot running pressure might be 75 to 85 psi.
With early warning if you loose about 3 psi or more from the higher, hot running pressure in a couple of minutes you get a warning. So in this example you would get an early warning at about 77 psi. Well before you are doing damage to the tire.
Some systems only warn after you have lost 15% from the cold pressure or in this example you might have to leak down from say 80 psi to 55 psi before you get a warning.
Based on the above I bought the TireTraker
Note I do not work for or sell any brand TPMS.