1) Unless it gets covered in mud, infrequently. Usually before dropping it off for tires or if I'm going to be working on it. If the car gets washed I'll often wheel out the bikes and wash them as well.
2) Have a chain oiler. "Clean" is wipe down with a paper towel as a gas station if it's really dusty (often is here)
3) ATF Relatively cheap, doesn't attract dirt badly, very consistent
4) If you really need very dirty to very clean, truck wash is the go to BUT you have to wash it off completely afterwards and ideally ride the bike until it's dry. (Tends to eat aluminium if it's left on there)
2) Have a chain oiler. "Clean" is wipe down with a paper towel as a gas station if it's really dusty (often is here)
3) ATF Relatively cheap, doesn't attract dirt badly, very consistent
4) If you really need very dirty to very clean, truck wash is the go to BUT you have to wash it off completely afterwards and ideally ride the bike until it's dry. (Tends to eat aluminium if it's left on there)