I'm on year 3 with some AGMs. I bought used group 24 AGM batteries from a local used/recycler battery joint that were used in large hospital battery backup applications - they're typically never cycled but once for testing and always kept topped off. Very common to find these kinds of batteries in bulk a few times a year where I'm at. The flooded batteries (mostly Interstate) that I used in years prior would last at most two years even when properly maintained. The FL heat just nukes those things.