I buy the Walmart batteries too. I keep my batteries on a battery tender year round when I’m not in my boat. With that said, I usually replace my Walmart batteries by year 4 because I start noticing a weakness. I use Walmart for the ease of returning a battery should I get a bad one. Until I started using a tender, my batteries would last maybe 2 years. Freezing cold is hard on an uncharged or weak battery