More on the "24 hours" thing: In SH2 all missions were single missions, strung together to make a "campaign". SH3 was planned to be similar, but got changed to a dynamic random campaign. The "Patrol for 24 hours" is what was left of that. In real life you would be assigned a grid and expected to stay there until ordered to go elsewhere. The renown for arriving and for staying is eliminated in GWX.
That said, some people (me) go and stay for weeks, even if they don't see anything, some do the 24 hours and move to better hunting grounds, and some never go to their grids at all, figuring they'll get more renown from sinking ships.
It's a game. What you do is up to you.
