Let the record show that (1) I have carried a tire gauge in fact, the same tire gauge for about thirty years, and on occasion I bring it to the local tire shop, which will happily verify its accuracy. My car is not quite that old, but it dates to well before the widespread adoption of tire-pressure monitoring systems, which are now mandatory on passenger cars sold in the States. And up to now, I’ve never regretted not having one, but that was before I saw TPMS v2.0:
This neatly solves the one annoying aspect of old-style pencil gauges: you have to stop filling, apply the gauge, start filling again if you’re not up to where you’re supposed to be, lather, rinse, repeat.
Of course, by the time I’m ready for this, I hope I can also get my own in-house nitrogen supply.