Being it is a lipo battery, I would not go by voltage. The voltage drop off is pretty fast with lipo. I would do a full charge then make a few flights and then charge back to full capacity. The amount of current it takes to top off the battery will give you a good idea of how many flights you can safely make before recharging. If the battery is in good shape, I would think that a couple flying sessions per charge is no problem. Better to run the test though.