If I was to buy a used unit from say CL and the sell stated it was kept inside and maintained, I'd want to see where it was 'inside' at and maintenance records or at least some half used tubes of Dicor or Sikaflex..
It takes maybe 5 minutes and a ladder to see if it has been maintained.Not everyone uses the products you listed..Say grandma had the RV dealer re-seal and maintain it's more than likely they used some form of silicone...Oh ya...That nasty eight letter word on RV forums.(laughing) but it works...
Either way,one can tell in just minutes if it has been maintained especially on the roof.
