Best overall bang for your buck is...
Annual roof cleaning and UV treatment is all that is required IMO.
Don't forget a quarterly roof inspection and Dicor sealant touchups.
You could also be an excellent candidate for Eternabond.
Lou and Laura with Bella - German Short Hair Pointer
2008 GMC Sierra 2500HD Crewcab SB Allison Duramax
2010 Flagstaff 8526RLWS - Superglide 3300
HAM CALLSIGN - KC3FFW