At work, I found out that my Milton inflator gauge was reading very inconsistently, sometimes right on, others high by a few pounds. I have gone to using a cheap-o, old school pencil type gauge, and it's always within a pound of what the TPMS sensors read on the cars. $50 Milton vs. $$5 pencil type. It's much more convenient to have the gauge in the device that you'll be inflating with, but accuracy is much more important, especially when the pressures read on the dash, and people could see that your gauge is wrong!