TV battery life? And Interstate longeivity? Diesel trucks.

I'm on my third set on my 2003 duramax. I live in florida and haven't notice much problems with the heat killing batteries. I have a set of group 29 in my boat which I used a year in the camper prior to switching to 6 volts. The sticker is 2010 so I'll probably replace them this year as there not anything worse then a boat that won't start when offshore. The one problem I have noticed is motorcycle batteries not lasting more then 3 to 4 years. I do use battery tenders for batteries not used often.