Long life paint sealing is a great way to make future cleaning far easier, plus some protect against the suns UV rays which is one of the main problems in the industry.
We seal new and old caravans but the older ones are a lot more work. Each job should take around a full day to finish correctly in our opinion. When sealing an older caravan, we have to go around the full van with a UV light and mark all the paint defects like bird lime defects, scuffs and awning pad marks. These areas then have to be corrected with a machine mop and specialist compounds. We would also never seal a caravan that had any dull faded panels. These would also have to be restored again with the machine mop. Once the paint is perfect, then it's fine to fully seal the caravan. I will add the same methods are used on new caravans because they are not immune to defects in the paint finish. We always say that 80% of the working job is the prep and 20% is the sealing work. I am a big fan of these products and we ran a 12 month test before we started using them. Myself and all my guys who own caravans have all used this treatment on our own caravans and we are impressed with the results.