I'm about to replace a battery in a Pokemon Emerald. I was wondering how long these batteries (CR1616) will last. (I would look it up myself but my school blocks almost everything that isn't educational. Minus this site.)
I believe the answer you're looking for is anywhere between 10-20 years. These batteries are still only just starting to die out from the launch of the game, so if that's any indication you should be set for a while.