[aidenn0]

I heard a (possibly apocryphal) story that the 1XC series calculators were specified to only need a battery change every N days, and the engineers interpreted that as working while being on 24/7 for N days. Battery life in them is so absurd, I suspect that shelf-life of the button cells may come into play as much as the drain that the calculator itself uses.

[dublin]

The batteries in my wife's 12c have only been replaced two or three times since she bought it in college in 1984! She worked as a commercial real estate appraiser for many years, using it daily. A few years back, she started a new job doing something similar, so it's back in use again, good as new.

I fully expect it to outlive both of us - due to HP's excellent dual-shot key molding that embeds the key legends into the keys themselves, it looks nearly new less a few scratches and dings imposed by the real world. This may have been one of the last times a product was truly designed to last indefinitely. And yeah, I suspect self-discharge of the batteries is at least on par with the actual power usage of the calculator...