Cycling Batteries are a very good practice and Will give you an pretty accurate Measure of Flightime and Capacity Percentage...But I recently Bought an Aurora 9 Hitec Radio And It has Onboard Voltage measurements While You are Flying (Realtime) And If you have Battery Issues Or a Servo Fails Or a Linkage gets stuck and Starts Overdriving the Servos The Radio Warns You Starts Beeping when You have a Problem (Voltage related Drop) and Gives you a Heads Up!! It has Already Saved a Plane I would have Otherwise Lost.... Thanks Hitec ... Spectrum has Also Come out with a Telemetry Equipted Radio...It will Save your plane If you have a sudden voltage drop..... pretty cool stuff... My Voltmeter is always reading my plane ...