My OEM batteries lasted 18 months on my 1996. I replaced them with Optima red top batteries. Those ran flawlessly until early this month (June), when I replaced them with another set of Optimas and relegated the old ones to my travel trailer tongue. (I know they aren't deep cycle, but so far, so good. )
The heat here in central Arizona eats lead-acid batteries. The kind you can't add water to are the worst.