For me, hub and headset twice a year (British weather= wet in the summer and wet and salty during the winter). Hollowtect cranks, remove twice a year to check axle, clean and refit. Same with jockey wheels. The only parts on my bikes that get 'regular' attention are the chain, cassette, chainrings and mechs...involving a bucket, water, sponge, kitchen detergent and Finish Line Cross Country Wet Lubricant.