I checked my cranking battery and it was a 2012 as well as one of my trolling batteries and the other that is still in good shape was 2010 that came when I bought the boat.
I think I am just going to replace them all and be done. In the back I only have room for a 12-12.5 inch battery. It has group 27 in it. What is the best bang for the buck that will fit? I could move them to a compartment right behind the front pedestal and have more room but that is a lot of weight far up front.