When your passengers smell better than you do !!!!!
When other pilots who never even acknowledged you before start calling you "mate".
When you no longer have to put the covers on the aircraft at night.
When just the thought of having to do an NDB approach fills you with dread.
When an extra 10kgs of baggage is of no consequence.
When you no longer have to contemplate ditching if you lose one engine on take-off.
When you don't have to consult with your passengers regarding the exact location of the airstrip.