I have a 00 Pontiac that the battery was changed in 02 or 03 with a Die Hard, i got it in 05 and its still in there.
It has never been on a maintenance or any other charger or jump started, even though it sits 5-6 mo a year and does less than 3K a year it fires right up every time.
I could put a new one in today but I wont, now its almost a mission to find out how long it will go, at the first sign 0f weakness its gone.