We are having this done as well.
We have a very good friend that happens to work for an RV company as a repairman. He got up on the roof of our camper last month and told us we needed to have the entire thing scrapped and resealed. He said it's just maintenance and needs to be done every 3-4 years. We've had if for 3 seasons now so I guess it's time to get it done.
Funny thing is, if the RV company had suggested we get this done, I would have been convinced that they were looking for money; but considering it's a good friend of ours, I know he's being truthful.
We are very handy and do most work ourselves, but we decided to pay someone else to do this job. Don't have the time or desire to stay up on the roof for 8 hours scrapping off old caulk.