Digital calipers can only measure relative position changes (by counting pulses) and would have to be re-zeroed every time when turned off. Since a well-designed pulse-counting circuit can run for many years on a coin cell, it makes sense not to have an off switch, just like a wristwatch doesn't. The problem is that for some reason the companies making cheap knockoffs don't manage to keep the idle power consumption as low as the name brands.

I need to re-zero every time anyway, so I'd rather not have to replace the battery every few months.

Really, I'd like a mid-range model; not a cheap one or a cheap one sold for more, and not a high-end one, just something that works reliably and repeatably, and doesn't chew through batteries. I have a ~20 year old (guess) set that fits this description, and several newer cheap and crappy ones that do an okay job if you keep spare batteries on hand. It seems impossible to find more like that old one.

Sounds like the battery hassle alone is enough to make some Mitutoyos worth it.

It doesn't help that my batteries come from AliExpress. I don't use the calipers enough to justify the massive price of Mitutoyo ones.

Does that really address a problem? I have a no-name set of calipers and the battery has been good for at least a decade.