Casio F-91W, is one of the classics. It was one of the better first mass produced electronic quarz-watches widely affordable. When it appeared in the late 80s(?) it was a symbol for real nerds.
Remarkable to me is that Brian Kernighan wears one. (In videos with him look closely at his watch.)
You see, BK may be no billionaire, but he is for sure not a poor guy. For sure he earned good wages for all the jobs he did, and do. Just for "The C Programming Language", of which millions of copies are sold, I guess in theory he easily could afford a Rolex. But he wears a supermarket watch for a few bucks.
Because it's battery powered electronic quarz driven it's more precise a than any mechanical watch can ever be.
This watch does exactly what a watch is for: tell time, and date (and I think it comes with a stopwatch, too.) Plus you don't need to bother of anything, besides to replace the battery every couple of years:
You will not be robbed for it, you don't need to worry about if it gets stolen, you lose, or break it. If so, you just get in the next shop, and simply buy a new one.
Brian Kernighan does not need to show off.
I find that impressive exemplary.