I had been thinking about trying it for a couple of years before I actually did, but I have always wanted to see how long the battery would last in this optic. The battery was last changed on June 18, 2019 as the yearly replacement and checked periodically during intervals when it wasn't shot. I had the gun out roughly 3 weeks ago and it appeared the dot was weaker than normal, so I took it out of the safe yesterday and it was completely dead. As I was taking the old one out I thought maybe it could have been a mistake to wait if the old battery had leaked (no idea if these batteries are susceptible to that), but everything looked fine and it fired right up when the new battery was installed. So roughly two years and nine months, and I now feel better about the ability of the optic to run well past my scheduled battery changes.