When I finally, after 50 years, decided to quit smoking, I did it by cutting down over a very long period, about eighteen months. I couldn't count on my memory to tally how many cigarettes I had smoked that day - too many interruptions could cloud the total. I needed a counter.
OK, at this point I should freely admit that I've got a good case of OCD. Trouble is I don't consider it a disability. Keeping things well organized is a real necessity in the sciences and damned helpful in the home and hobby shop environments.
The conventional hand counter, shown in the background in the photograph, is just too bulky to carry in one's pants pocket. What I really needed was something
with a slim profile
operable in pocket (so I don't have to answer a lot of stupid questions about what I'm counting)
provides tactile feedback when counting so I know the count has been registered
A flat aluminum plate was drilled with two circles of 24 depressions. The aluminum pointer is fitted with a spring-loaded ball bearing that indexes in the smaller circle of holes. Its clicking action provides nice tactile feedback. With a square profile the plate can always be locked between fingers and palm such that the thumb can push the pointer to count. Very light and flat, it's very pocketable.
I can't think of many metal shop uses for this tool. Perhaps counting full rotations of a mill handle when moving a long distance is possible. Regardless, people with many different hobbies frequent this forum so someone may suggest another use beyond smoking abatement.
Just in case anyone is wondering, I quit completely in 2010 and haven't smoked anything since then.