If you feel better charging after 2 flights then go for it, but I can tell you I have never charged a battery at the field in 20 years of flying, I don't even own a 12 volt charger. I have never lost a plane due to low battery voltage ( except one I forgot to charge before flying ). I have a 1/5 P-51 that has 10 servos and a 2700 - 5 cell pack and fly sometimes 5 or 6 flights and still have plenty left for 2 or 3 more ( according to my recycler ). I have a Balsa Nova 120 with 6 servos ( 3 digital ) and a 2000 - 5 cell pack and if it is the only one I take to the field I may fly 8 - 10 flights ( 10 min. ones ) and still have juice left.

After 5 flights I do however check voltage before each flight but once it gets to about 6.2 volts it just seems to stay there. I find the same thing with my transmitter it has an 1100 mah battery and will very quickly ( 2 or 3 flights ) drop to 9.8 volts and never go any farther even after 10 - 12 flights.

Someday I will lose an airplane I suppose and change my habits, but for now ( and the last 20 years ) "all is well that ends well".