> My Tandy Pocket Computer (a PC-8) still has the same battery in it that > it did when I bought it used. Granted, I don't hammer away at it I've heard stories of HP Voyager series calculators (10C, 11C, 12C, 15C, 16C) running for 15 years or more on the same set of 3 LR44 button cells. And being used fairly hard in that time. -tony