There is never a time when one truly MASTERS an aircraft, of any type. Sooner or later, ALL mechanical items will fail, airplanes included, leaving you gasping at the mess made on the field. There are points of being skilled, and being comfortable, but one cannot master a machine, only maintain it. The best "experts" at any given motorsport, can fail at any given time. If you have gotten bored with a trainer, switch to a more competitive plane, for a while, then go back to the trainer, and see if you don't crash it. True, while a trainer is just that, a trainer... it has its place in the sport, and one should NEVER get rid of their trainer... I have found them to be "hones" so to speak.