Another advantage of a Permit aircraft is that landing light bulbs can be much cheaper. The GE halogen bulbs from an aircraft spares supplier cost over £15. The same bulbs from B&Q cost £2.50.
Recently, after a long straight in approach with the landing light on, I was told by ATC that they could see the light before they could see the aircraft (remember rich?). I am happy therefore that these bulbs are perfectly adequate and,so far, bulb life has not been a problem.
The experience also encouraged me to use them more often.