Here' the deal with a tire pressure monitor for me. Before TPMS, I made it a habit of checking the pressures after a half hour on the road. After a while, I just checked the temps by hand instead. The TPMS saves me a stop, and even though I tried to find a rest area or someplace a half hour into the trip, sometimes I went longer and sometimes I pulled off on the shoulder, not the best place to do this.
I also found that obsessively checking tire pressures with a gauge was actually causing loss of pressure due to the occasional stuck tire valve. I determined that the tire shop did not put the correct valve stems in when they put Equal in the tires for balancing. In addition, I've had 2 valve extenders leak causing a total deflation on a tire each time.
So for me, the TPMS is peace of mind.