I have 4 Optima Batteries and they are all still taking a charge. The first two I had on my boat for over 6 years and now I keep them inside the house. I trickle charge them every so often. I replaced those with two new larger Optimas in my boat. Those are still working fine today. I have to charge them up every couple of months in the winter. I store my boat inside an attached but unheated garage. One of each pair is a cranking/starting batter and the others are deep cycles for my Min Kota Trolling motor.

AGM type batteries are the way to go.