Steve Turner wrote:

Shop with calipers.

Aye. I also need to carry a little pocket-sized tape measure with me
(like my Dad does), but knowing me I'd probably forget the dang thing.
I usually have to wander over to the tools section and "borrow" one of
their new tape measures, then put it back when I'm done. :-)

I've developed the habit of carrying a little 6' tape in my watch pocket,
it's now part of the stuff I always have like my wallet, keys, money-clip
etc. Somebody mentioned carrying a cheap caliper in the car--what a great
idea, I have at least one of those Harbor Freight digital jobs that cost ten
bucks, so in the car it goes.