I should point out that lifespan for the battery isn’t determined by age, but charge cycles. I ride 5-6 days a week, totalling around 700 hours a year. My 520 is well past the charge threshold, so battery life is only going to get worse. That said, I never got anything like 11 hours out of my 520.

My wife has an Edge 500 that was bought refurbished in 2015, and it could probably run for 20+ hours on a single charge. If you ride a typical amount, 5+ years out of a GPS unit shouldn’t be a problem.