Can anyone please tell me how I know when the tail motor is going on my CP Pro?

Thanks

a good sign that a motor is going is it gets very hot at the end of the flight. you'll notice you'll have to add more and more right trim throughout the flight to make up for the motor becoming inefficient at high temps. at that point it's best to replace the motor than risk an in flight failure.

the more careful attention you pay to the trim, the better you'll be at predicting motor failures.

how hot is too hot? I have my motor luke warm in flight and that might be because I have a heat sink on it.

Additionally how many flghts can one expect with a lithium configuration and stock N30 motor?

Vortex,
Luke warm is probably okay, it would be much hotter if you took the heat sink off. I've had my CPP for about 6 or 7 months, I'm on my third or fourth N30 motor. I had one motor that lasted only 3 or 4 flights. As Truglodite mentioned, for the price, it's best to just replace it.

Dave / Choppersrule

My motor lasted about 10 flights with one major tailstrike and numerous stoppages. It still works, but the heli requires almost full right trim to hover, and my flight times are noticeably reduced.