When I was researching the Phantom before I pulled the trigger I ran across an article that help put things in perspective about the hobby. Wish I could find it again. But one of the topics that has proved to be invaluable advise was keeping flight logs. I'm not talking about keeping explicit details on every single flight (not a bad idea either just time consuming) but more along the lines of tracking battery performance. I use a kitchen timer to track flight times...first a countdown of 7 minutes on my 2200's (9 minutes on my 2700's) then when the buzzer goes off I bring the quad back to me & I reverse to a regular timer adding the "extra" seconds. Does anyone else do this or am I just crazy? I simplified my own logs by carrying around a permanent marker and putting a line on each battery as I finish using it. I also have each battery numbered. I mark a long line for what I believe to be a solid length of time to shorter ones as the flight time gets reduced. This has served me well to track individual battery performance. Most of the time I can clearly see when the battery is starting to degrade by just looking at the length of the lines. Most of time time they are all trending towards ever so gradually reducing performance...with a few exceptions. Those exceptions are very interesting. I have a working theory that the slower I charge the batteries the longer the optimal performance but haven't been able to prove that just yet. I normally charge all batteries right at 2.0 Amps so I can move up or down a little to check if this is making any difference. Stay tuned on that..... These logs show subtle differences in flight times not massive. Think 30-45 seconds over several cycles. All but my newest batteries are on 50+ cycles each. Ironically, the original battery that came with the Phantom and my oldest battery is clearly performing better than all the others on longevity.