The last 3 operators I have flown with on 3 different continents including oz all had the same policy.
1. Nav lights on means there is live power going to the systems, be it from batt, APU or external. Next time you go get on a burner take a look. Reasoning, it is a warning to all, be it engineers, catering, refueling that there is live power.
2. Beacon right before starting engines
3.Strobes when entering the active.
4. Taxi or Landing lights ON On the roll to Top of Climb or through 10,000.
5. and a variation of either taxi light or landing lights on at top of decent or below 10,000' .
Simple really.