I think the longest I've had a lawnmower battery last was 6 years, and honestly only 4 of those years were trouble free. The last two if I didn't keep the battery tender on it, it would be dead in a couple days. When I sold it before I moved it had a bout 6 good cranks in it. If it didn't start by then, you were jumping it. My current mower just needed a battery the other day. It was only 2 years old, but the mower was infrequently used since it had a messed up carb. We'll see how the cheapie battery from Advance last; it will stay on the tender during the winter.