getting car ready for the winter and the year to come

just put new spark plugs and wires on the car...

but im wondering how I can tell if the dis cap and rotor need replacing...??

also have a question about how frequently the fuel filter needs to be changed??

Final question is about the products sea foam and lucas oil additives...ive heard using sea foam is great for cleaning out the fuel system without risking getting stuff messed up from carb cleaner eating gaskets...also ive been told i have a bad cam lobe so ive heard the lucas oil thickener will help keep everything well lubed...or are both products a waste of money???

thanks for responses as always