Well, unless that recovery will take time that they don't have (after all, while everybody hates timed missions, missions in which the enemy gradually grows in power are both realistic and far less pressing, while still making time into a real resource.)
Unless you plan on using Railroad Plot, or are currently in the middle of an active chase scene, this is not realistic for the majority of the campaign.
Originally Posted by The Underlord
All hail great Shneekeythulhu! Ia Ia Shneeky fthagn