I recently got a Palm m125, brand new in box, from eBay, for tinkering purposes.
The biggest hassle was setting up sync with the desktop, because that requires their app and drivers. But even that was ultimately a solvable problem on Win10.
But the old Palm apps install and work just fine, if you can find them. A more annoying problem is that a lot of them were shareware, and authors have long since moved on. But even with what's free, it's a handy little device; I can't think of many other AAA-powered gadgets that are capable of compiling C apps for themselves!
As far as battery life goes, I'll just quote one Amazon review from 2001:
> Another negative feature with this specific model is the poor battery life. The m125 requires 2 AAA batteries (included), however they only last aprox. 2.5 weeks under normal use (compared to the 1-2 months of the m105 and most other PDA's).
Sigh.