We had a triple EEE class C. It was a very nice motorhome, however we were fairly new to motorhoming and did not keep up with the caulking of the roof. It cost us in the end. We had to have interior ceiling panels replaced and wall panels replaced, as water had penetrated. An expensive lesson. So, at least once a year or every two years you may have to replace the caulking around roof vents and along all the roof edges. The roof had a large sheet of aluminum on top and those can tend to leak as well. We sealed ours with two different sealers before selling and moved on to a diesel pusher.
Bill