Navigation lights shall be illuminated on ground. On the boeings "navigation lights" means the red/green wing lights, aswell as the white beacons on the wingtips and tail cone.
The Strobe should be turned on when entering the runway (as with the landing lights), but on some aircrafts the strobe light has an auto position, which means that as soon the aircraft is airborne, the strobe comes on.

Anyone who flies realworld at night -- pax or crew -- will notice at altitude the strobes are turned OFF as they are quite annoying.

If the flickering light is reflected off any aircraft surfaces into the cockpit, it can affect the crews' night vision. We never had this problem in our Mooney as it's mounted underneath (the Cherokee, on the other hand, was another story).

bill
p.s. as noted, below 10k in  the CZ (Control Zone), usually everything is ON

In training I will use the stobes in daylight when close to the airport or if i know there is other traffic in close proximity.
I like to be a visable as possible! And because flying is relaitivly new too me I have yet to get the "hawk" eyes and sometimes have trouble spoting other aircraft real quick so I like too know Im doing whatever possible to make myself visable to all in the area.