I am quite fond of jet washing mine when really messy but not very often as it seems to be fronwed upon, that said, I avoid bearing areas and then carefully re-lube it afterwards.
The missus found the rear cassette in the diskwasher after the wash, she wasnt pleased but it came up like new !
I generally suspend mine from the garage ceiling and clean the gears with a rag, I do use WD40 on cable guides and for wiping stuff, seems to work.
Anyway, my regime is working, nearly 2000 miles/1 year and no discernible wear in the drivetrain, its still like new despite being used in all weathers, I cant see any wear in it, the gears still shift perfectly and contrary to some stuff I have seen on here about replacing stuff after a couple of thousand miles. In fact my gears shift better, unadjusted from new than the Ultegra kit on the sub 100 mile Felt F65 I used on Friday !