I'm aiming for maybe a 1-2 month deployment for larger ships w/o freighters and such. Frigate and destroyers can spend less time on their own, while fighters obviously need support due to not having any cargo capacity.
Of course, that time greatly depends on the repairs that need doing, and whether the fleet sees a lot of action.
The ISS Black Star might not be quite so independent, then. The idea of a lone ship against the world has romance to it, if not necessarily logical sense. Perhaps there could a skill for reducing the costs of the piloted ship alone, to provide room for one-ship fleets.
Then again, the Max CR supply reduction might be enough on its own. There may be only one battle between resupplies, as I figure the standard mercenary life is as following:
1) Find mission.
2) Blow stuff up.
3) Return to base to repair, refit, and refuel, then back to 1).
This is, of course, if everything goes right.
@Decer304: Currently, repairing fighters does use supplies, and it says so in the battle messages. It doesn't give an amount used after battle as far as I know.