Also a very good habit:

I always have a flightlog on board that I read after switching the system On. If one antenna shows ---- this means that it is inop and has to be changed ( or there is a cable problem ).
I record the Flightlog data after each flight and check the trend ( I also record max EGT in flight, max EGT during start, max pump voltage and min rx bat voltage from 2 voltspy or similar device ).
All of these data show usefull trends...