It depends upon what you are paying for and how much. If the service include you to taking the coach in for an exterior wash so many times a year for the 5 year period, my not be a bad deal considering how much it costs to clean. Here in central California there used to be a dealer that offered such a plan. Exterior protection and unlimited exterior washings included. Dealer no longer in business, but back then it was a great deal if you were located close by.
Presently I pay $80.00 to have a service come to my residence and wash the coach roof included, $280.00 additional to hand wax, totaling $360.00 so I give them a $40.00 tip to round out to $400.00. Being my coach is enclosed from the elements, I don't have to wax that often.