When starting engine..
 

For some odd reason I have always believed it was better to turn off my a/c or fan switch when turning off my car rather than starting it up with it already on, does this make a difference or no....

Personally I make it a general practice to shut off all electrical accessories when turning off the engine.

I leave the fan on but turn off the A/C compressor at least 30 seconds before shutdown. Usually when I turn onto my street or about to turn in to my destination parking lot. This gives some time for the fan to remove condensation and for the evap coils to warm before shutdown and it ensures that my compressor is not on during startup because I may not need it on my next trip.

The fan, radio and compressor are all powered down during the START cycle but come on immediately when you release the key to ON position.