I got this fancy tire gauge+filler. It uses a couple coin batteries. They live around 6 months with it "off". I use it a couple times a year, so basically every time I go to use it it is dead. Removing the batteries requires disassembly. A year or so ago I soldered in a couple AA batteries in place of the coin batteries, it's been good so far, but I'm waiting to see.
On the other hand, I have a Mitutoyo caliper, which also uses a couple coin batteries. I sometimes forget to turn it off when I put it back in the case, and so far, over 6+ months, it hasn't run the batteries out.
So it CAN be done. Both devices are basicaally the same: LCD display and they measure a sensor.
Back when I was in HS, I had a Casio calculator watch, but it ate through batteries (3-6 months IIRC). The bracket for the strap broke, so I just taped it up in my locker. Soldered it to a D battery, and never had to replace it again. :-)