Sorry for the double post, I cannot edit after a certain amount of time for some reason. Out of curiosity, what would happen if I didn't do anything about the battery and let it die? Would there be permanent damage? What would happen?
No, you'd have no physical damage from a dead CMOS battery, you'd simply lose your BIOS settings, Month, Day, Year, Time, boot order, things of that nature. It would make operating very frustrating.
Personally, I replace my CMOS battery about once a year, so it doesn't die on me when I least expect it.