Epaulettes
Whether to wear them? How many bars?
I suppose of you are routinely experiencing some difficulty in passing through the various checkpoints in your shorts and deckies - some airports in France for example? - then it might be prudent to wear an airline shirt, sensible trousers and, as a captain, 4 bars.
If you just want to look like a pilot to impress then wear them all the time. Some will take the p@ss, I probably would too.....
HP