[FullyFunctional]

Me too and ... it's still working on the factory batteries!

There are many reasons to love the HP calcs, but I think the keyboard doesn't get enough praise. I have never found another calculator as satisfying to use. I heard from owners of the Swiss that it's not quite as good.

[fmajid]

Me three. The reason why those calculators last so long is their use of silicon on sapphire technology.

FYI the company that took over the HP Calculator business is releasing a "HP-15C Collector's Edition" that fixes the HP-15C Limited Edition's bugs, but it's a limited edition as well so if you want one you'd better preorder. It won't have the amazing battery life of the original, but it will be orders of magnitude faster, and reports say build quality is good, unlike newer HPs.

[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...