Your car has a large fuel filter-given the relative quality of fuel today, it should last 100k miles easy! Heck, if you buy a new Honda Accord, it has a similarly-sized fuel filter which is expected to last the life of the car! Then again, a Honda Accord usually dies because its body falls off
I suppose if you don't know the age of the filter, replace it. I'd also replace your gas cap, as it should seal perfectly and eliminate any concerns regarding moisture being absorbed that way.