Well sometimes they just check them with a volt tester. If they used a load tester and they were good, save your money and keep using them. The key is to keep them charged after using them and topped off with distilled water. Charge them as soon your done fishing. Some folks get done and put-up their boat and don't charge until next time they get ready to go next time. A trickle charger when same you $ in the long run. By the way, I always get mine at Wally world and never had any issues. Im sure you'll get other advice.