I learned the hard way about regular re-sealing. Have always kept my TC in covered storage. Last year had to rebuild lower rail of cab over portion. No indication of trouble, till siding seam opened up on the "nose". All upper areas were fine. We believe water got under vinyl screw cover strip on corner molding. What a pain! Had to carefully pull siding from nose section, rebuild framing and reinstall. Of course that means removing all the windows, and hatches, cleaning or replacing, then resealing.
I was impressed with S&S construction under the skin. Especially bedding around those signature front windows. No leaks there.
My caulking is not as pretty as factory, but I know it is sealed!
Think about all the stress and strains....along with "Hurricane Force" wind (60+ MPH) as we go down the road, load and unload. It is amazing how long our TCs do last!
I'll be cleaning, and recaulking at least every other year now!