FWIW I have more than one set of digital verniers which are either used very intermittently or where the battery only lasts six months or so. I have used cheap batteries (eg from the pound shop) but it still irks me that the batteries clap out so quickly. It also irks me that I end up with various batteries that I don't need when I buy a card of them from the pound shop.
So my latest wheeze is to use some of the thinner batteries (which are otherwise the correct diameter, voltage and polarity) together with a spacer such as an 'O' ring to make up the thickness difference. If I am not going to use the calipers for a week or so, I'll take the O ring out (which usually moves the battery off its seat and turns the thing off) and I then stow the O ring somewhere convenient like over the locking screw knob. Hopefully if I do this I won't be having to change the battery so often, and I won't be left with so many batteries that I'm never going to use.
Of course I'd be even happier with a proper 'off' switch but I suppose that would cost money....
cheers
cheers