Should Caulk be used around vinyl windows
You don't have to caulk something just because you normally caulk it. There is a reason why everything is done and learning this will save you time and money. Since you've had the home for a year already, I'd guess that you know if water leaks in or if you can feel drafts near them? If so, caulk it. If you have a reasonable doubt that they might not be installed correctly and could lead to water problems, go ahead and do it. Like you said, it'll save you from the experience down the road, but it might not be needed.




  VINYL WINDOWS AND VINYL SIDING
  
  Vinyl windows, if installed correctly
  shouldn’t need to be caulked in too many places. Caulking on the
  interior is mainly for aesthetics. You will caulk where the drywall
  meets the frame or the casing meets the frame. You can use some
  painters caulk on the inside where the window meets the casing or the
  drywall. If it was installed correctly there shouldn’t be a draft
  coming from this area.
  
  
  
  WOOD WINDOWS WITH WOOD SIDING
  
  These windows require a lot more maintenance. All gaps should be re-caulked. If caulking after painting or if you have natural wood, you use a clear caulk. If caulking before
  painting you should use paintable caulk rated for exterior use.
  
  
  
  REPLACEMENT WINDOWS
  
  Replacement windows are installed in existing wood
  frames. The windows come as a unit and should be caulked properly when
  installed. In situations with replacement windows, you have the area
  between the new window and the existing frame to keep caulk maintained
  as well as around any old trim.
  
  http://www.handyguyspodcast.com/839/episode-94-caulking-windows/