I received my HP-11C calculator as a gift in 1981 while studying physics at Central Washington University. I used it intensely for my four years at the university, and have used it as my main calculator ever since I graduated. I have never changed the batteries in the last 25 years! Every day I turn it on and wonder if it will be its last day – but it just fires-up and is ready for work. I’m not sure if there are any records for battery longevity, but 25 years seems like an awfully long time. I’m not sure if it’s a testament to the 11C or to the batteries; my guess is both can share the credit. If anyone has a similar story for 25+ years on the same batteries, let me know.
Edited: 15 Jan 2006, 4:05 p.m.