Arcane Connections may be fixed in 1 week, rather 1 season as the MRB indicates, they still cost 1 pawn of vim vis. For connections lasting hours, the process must be initiated quickly and the pawn of vim vis spent. The rest of the week is spent attuning the connection, for lack of a better word, if the time spent doesn't happen for some reason, the AC is lost, as well as the vis.
That being the case, don't go crazy with 'em. If done during a season of labwork, they count as a distraction, and penalties to labwork may apply. It may be possible to fix one during a Princeps season, but to do so, you'll have to work in the lab and not be interrupted, requiring you to negotiate with the vice princeps.