I believe it is a "new topic". If not, apologies.
I've seen the HP 50G described as "a battery eater". Accepting that as the case, the AAA battery's "service life" described as perhaps 4 hours, spare batteries or rechargeable types are a solution to that problem.
What I'm curious about is the life or "service life" of the "memory backup battery", also known as CR2032, the round wafer battery that resides under the battery compartment. I have rechargeable AAA's in the calculator, along with a spare set of AAA's and a spare for the CR2032, but am curious as to how long the "memory backup batterry" might last.