I bought a MPro in 2017, and basically only use it when travelling. I've only done 12 hours of flight with it, in 6 countries, but we have an upcoming trip (Ireland), and digging it out again, reminded me that I'm down to 2 batteries (at last check, need to fire it up again to make sure the remaining 2 are still functioning). I don't do video with it, just basically stills from vantage points you can't get from the ground. Am I better off investing in a couple of new batteries, or looking at one of the newer, but used Mini or Air?