@hazelton For many years I carried a 6" metal scale in my pocket (marked down to 1/64ths, so not as fine as .1mm!; inches are the customary measurement here). I stopped because it kept cutting holes in my pockets, but it was indeed convenient to have. It is now sitting beside me on my desk, and I have various inch and metric scales at my other desks. I always pick them up when I find them at flea markets/estate sales/etc.!