Our Hymer is 5 years of age this month and it is booked in (this coming tuesday) for a 5 year service with cam belt and tensioner change, checking the water pump & change if required as easier when doing the cam belt.
It has only done 14800 miles. Better be safe than sorry
And it is for sale, so any prospective buyer will know that she has been looked after regardless of cost
And if she does not sell, we have a m/h that we know is as good as can be

Oh I forgot to say, the brake fluid is to be changed and also the air con is to be serviced, all extra