Kind of agree with this now, had expensive cars and worried whenever I returned to it, changed job and needed a workhorse, E Class estate, abuse it really and now worry far less about odd chips and dinks, still like to keep it clean though!
TBF nothing is going to prevent a dent, or scratches, without PPF, even then dubious.
I guess we need to know the car to be protected and budget to do so before proper recommendation.
Really depends on what you want to do.
A professional polish, and ceramic coating with something like gtechniq could cost from £850.00 to £1500.00.
Something like cquartz uk, (a very good ceramic and easy to apply, even I've done it) which could be applied outside if temperature is within...