I can only speak for my procedures on fiberglass roofs.
I have had 1 truck camper (rubber roof) and 3 RV's. The first had a fiberglass roof, the 2nd a rubber roof and my current (PC 2551) is fiberglass.
My first fiberglass roofed RV I bought new and used for 9 years. This one (the PC) I have had for 4 1/2 years.
Both are/were stored outdoors in Colorado, both at about 5,000 foot elevation. I have done nothing to either fiberglass roof except clean it with denatured alcohol when I had a seam that needed recaulked. Never had a roof leak, never saw any cracks or delaminations, etc. One a year, I would wash the roof with just car wash.
Never waxed, never used a coating. I would think waxing would be bad as wax is difficult to remove if you have to recaulk.
The rubber roofs needed much more maintenance. I never coated either rubber roof, but with the RV rubber roof, after about 6 years, it was due for a good recoat job. It had become dulled and scrubbing got a white powder off it.
So.. Just my opinion... Just clean it real well where you are going to recaulk, wash it once a year, and you are done.
Obviously, if a leak develops or you see an issue while washing... Take care of that. Otherwise.. Leave it alone.
Your Mileage may Vary.