I had mine recaulked late in our first summer with the rig. Probably got stroked on that, but I kinda owed the mobile tech that did it for other reasons. Late this past summer, I redid all of the roof caulking by cleaning the existing stuff and laying a topcoat of Dicor Self-Leveling over it. I didn't have any leaks, but it was starting to show minor spider cracks, so I did it. Wasn't expensive since the Dicor rep at the 2013 Goshen rally was handing out tubes of caulk to seminar attendees. Actually got enough to do the whole job!
I went around the windows with BOSS 378 caulk. Some were starting to show a little separation between the caulk bead and top frame. So I cleaned that caulk out and applied the new. Same with the vertical trim on the front & rear caps.
Checking and recaulking when needed is worth the effort and expense, rather than waiting until you see interior damage that will ruin your day.