The Mini-Lathe DROs eat a 390 alkaline coin cell a year, more or less:
The other DRO’s cell was 10 mV higher, so it might have survived another few weeks. I’ll call it a year, as the OEM cells failed half a year after I got the thing and these are the second set.
The last time I did this, I wedged a thin foam sheet below the display PCB to put a bit more pressure on the (+) contact tab sticking down from the middle of the plate:
The (-) contact is a pad on the PCB below the battery compartment. The glaring metal reflector is part of the curved cell retainer.
I still wish the DROs didn’t collide with the compound slide, but you can get used to anything if you do it long enough.