A battery of that age is at or past it's normal life. Have it tested and be ready to replace. Of course, replacing it now may avoid getting stranded somewhere therefore be worth the investment now. If it was mine I would replace it now...but that's just me.

 

I'd wait and keep an eye out for signs of failure. After all, it's not like it's a transmission.

 

I will follow your advice zman, I'd like to hold off on the new battery until this one actually sh*ts the bed. For being as old as it is, it still starts the truck just fine every morning outside and that's after the truck has sat for a week. Funny you mention the transmission. This being my first Dodge, that was the one thing I was deathly afraid of when buying a Ram. Mine has 142,000 on it, never been rebuilt and it still shifts like a dream.