I find that a fendered bike with high quality sealed bearings, Trek BB90 fiasco excepted, is not hard to keep maintained. The chain is the biggest challenge. if you do not have a front fender with a mudflat, the chain is going to be sprayed with a slurry of sand, soil, and "gunk". This means taking the chain off and cleaning it and lubricating after such a ride. However, I can get away with a simple relube when the bike has said fenders. On my recumbent, the chain is higher and survives wet weather much better. The water off the front tire hits me in the derriere. I find sealed derailleur pulleys to survive wet weather fairly well and worth the cost. I also replace the junk bearing mfg and bike shops use with high quality ones and that also helps.