My application is 3 years old also. In that time, I've scrubbed and just re-applied the top of the front cap twice. I have a bra on the rest of the front. I'm sure its because of my agressive attack on bugs. :)
My front door flaked badly after only a year or so. I believed it was because of poor preparation on it on my part. For that I stripped it with the Red Max Stripper. Pretty simple job, messy but simple. Re-applied the door and it is now holding up as well as the rest of the MH. BTW: We fulltime and its exposed to elements all the time....except snow :)
I'd suggest washing an area with dawn and re-apply several coats and see what the results are. If not acceptable, you know you have to strip.
