10- to 15-year-old battery advice would concern lead-acid, nickel-cadmium, or nickel-metal-hydride batteries and would be completely different from the links I've posted above, because those battery types need very different treatment from the lithium-based batteries used in all modern notebooks and other portable electronics. I agree with Scott that obsessing endlessly over one's battery is a waste of time and energy, but calibrating it often enough so that its condition is reported correctly and avoiding practices that will dramatically shorten its lifespan are not. You don't spend time every day thinking about your car's next oil change, but if you're smart, you check the oil level occasionally and you have the oil changed every few thousand miles. Give your battery the same level of attention.