Wife gave me an F6 oh 3 years ago? 4? The watch battery died last summer; but I was having an off-season and didn't mind. I just replaced that battery today, and verified that the cheststrap is still working. Great, as this is definately a biking season for me (and I'm trying hard to lose weight). My question is, should I buy a spare cheststrap on the basis that it's 3-4 years old; or is the battery life in standby mode really that good?

The manual says 2000 hours, but clearly that is hours excerising. 4 years is within the shelf life of most batteries--but this isn't quite shelf life (non)usage. Obviously I could just buy another, and let it sit in a drawer; but then it's the same "battery is running down anyhow" issue.

I haven't a clue just how much I used it. Couple hundred hours, tops? Conservative (IOW long) guess is 300 hours.

Yes, I can just run it until it stops. Probably will. Mostly curious--if 9 out of 10 people say that shelf life is 10+ years, great; if 9 out of 10 say shelf life is 4 then I'll just order another.