If the rain has stopped I'll pack up the wet tent and plan to let it dry out later (either at lunch or by setting it up as soon as I reach that evening's camp site). If the rain is still coming down I'll base my decision on the circumstances - do I need to get somewhere that day (reservations, previous plans with others, etc.), does the rain look like it'll end soon, how hard is it coming down, are there safety considerations, etc.