I wave a power washer over my bike when it's really crusted with dirt. Usually every 4 or 5 weeks in the winter, maybe twice between April and December. I lube the chain when it makes noise. I replace the entire drivetrain when it starts to skip (about every 9000 miles - I've tried also maintaining the drivetrain diligently and replacing the chain when the Park tool says to, and the drivetrain still needs complete replacing at 9000 miles, I have just bought 3 more chains in the mean time for no better operation).

I've never used anything but a blast of water on the bike, or at least, not for years. I actually tried to clean it once and after about 30 minutes decided "screw this, I don't really care that much."

It has 28500 miles on it after 8 years and I haven't yet had any issue that could be tied to dirt or lack of maintenance - I had broken spokes, a broken axle, and I stripped the pedal threads out of a crankset once because I changed pedals in the garage when it was -15*F once and the aluminum had bonded to the pedal (I now heat the aluminum with a torch if I need to change pedals when it's that cold).