If you have a Turnigy 9X RC transmitter, be sure and keep an eye on the operation of the power switch -- especially if you haven't used the radio for a while.
Unfortunately, the very low-cost switch used in these transmitters tends to suffer from contact oxidation which can result in intermittent operation. A squirt with a good quality contact cleaner and lube (CRC 2-26 works well) and some brisk exercising of the switch will do wonders.
Also, remember that if your RC system has a failsafe capability, *DO* use it. It could save your model and possibly even save a life in the unlikely event that something does go wrong.