Dealer Paint Protection = pure profit and BS.
Don't let them suck you in. Any good detailer can do it at a fraction of the cost. When you apply sealant or wax, 90-95% of the finish and how long it will last depends upon the preparation. ie ALL contaminants must be removed. The shortened version is wash/clay bar/machine polish/cleaner fluid - to prep the surface for correct bonding of wax/sealant/ then LSP (last stage product ie wax/sealant).
No wax or sealant is going to last longer than 6 months , wax will be more like 3 months. Once you have done the correct initial preparation then every month or so a top up of the sealant or wax is ok without having to go through all the steps again unless it is obvious the paintwork looks dull/contaminated.