My UPS just sits there quietly most of the time and I don't even remember I have it until the power goes out and it keeps my modem working. Today I replaced the internal battery after fours years of operation. I didn't receive any alert that the battery needed replacing, but four years is about the lifetime of a typical UPS battery (three years if operated in a very warm climate) and I didn't want to have the exposure of a low battery that would not sustain a power outage. It was a simple matter to buy a replacement battery online at about 40% of the price of a brand new UPS unit with battery. Don't feel like you are "cheaping out" by replacing the battery instead of replacing the entire unit. My APC unit is designed for replacement of the battery and it's a very simple process to remove and replace it (see your instructions). It took me less than two minutes, and you might get lucky and find a Youtube video showing how it's done for your model. I spoke to a technical rep at APC and he advised to replace the entire UPS unit after 8 years. So that means you can change the battery at least once before buying an entirely new unit.