Fibreglass and gelcoat needs to be regularly cleaned, waxed, and polished to protect the surfaces and keep it looking loved. Unloved gelcoat can become chalky and this is difficult to correct. Preventative maintenance helps.
Dodgers, sprayhoods and screen and hatches can deteriorate quickly if not care for. Use the correct polishes and cleaners to prevent canvas degradation and prevent the plastics becoming opaque..
Upholstery and vinyls need to be cleaned several times a season, it's worth investing is some Scotchguard fabric protector to keep the worst of the stains off the cabin cushions. Always use the correct cleaners.
Brightwork, all the wood and trims that are exposed to salt and UV require quite a lot of upkeep. As with most things the more expensive the varnish or oild, the better it will perform.
Stainless steel needs care too. It's not supposed to rust but will degrade in appearance if left. Use a good metal polish