[seafarer]

I have to admit that I too don't do the mid-patrol refit thing. Whenever I run out of torpedoes or low on fuel, whichever comes first, I rtb and end patrol.

I know there were instances of refueling and re-provisioning during patrols, but such things seem pretty rare from my reading of WWII operations, so I tend to play with the realism in mind.

But, if you want to keep refitting and heading out, it's up to you. Then, as to when to end the patrol, again, it's purely a matter of personal preference.