Hello Joe,
Servo wear being an issue is a simple fact of life in Pattern. We ask for great precision, and the airplanes will misbehave when servo centering starts to degrade with gear wear or feedback potentiometr wear.
With wet power, it was typically every 75 or 100 flights! With E-power, this has gotten better, but not been eliminated as a necessary bit of maintenance.
Often the degradation is subtle and gradual, so periodic servo sweep tests are an excellent idea.

Regards,
Dean Pappas