Does anyone have a ballpark number of times they use their phantom 2 remote before replacing the 4 double a"s. I know they have a indicator when they get low but how bad is the situation when that happens?
Typical alkaline batteries will last around about 20h of usage. Personally I use rechargeables, and replace them after 15h to give a reasonable margin of error.
Rechargeable batteries are not recommended, as their terminal voltage is lower - 1.2V compared to 1.5V. The current draw is very low, so you can run alkalines or lithium batteries.
I have a set of Energiser lithiums that so far have done over 20 hours and still read 6.2V!
TBH, I don't think you will ever have any issues with rechargeables, but unlike older TXs, these sets are designed for alkalines. The way the TX modules work, it won't make any difference on range, as the TX is fed from a regulated supply to give an unchanging signal - at least until the battery voltage dips below 4.8V!
I always keep a backup set of 4 in my Phantom's carrying case.
A very vague ballpark for you is that I had a set last for a month of use, flying once or twice per day; that's in line with a previous reply saying ~20hr