Asbo's got it right, the company wagon, a beemer gets the odd machine wash for £2.90 as and when, I did have it valetted at work for about £40 because even I felt it was too dirty inside (blaming the kids this time)
Mistermog gets washed when dirty usually a pressure wash job, 5 stages for 5 quid including a wash wash. just last week I did a big job and out with the autoglym stuff, brought the body up lovely and used the autosol on the metal bits, like a new car, the wire wheels got a cursory treatment and I have traces of rust on the chrome rims, leather gets a wipe over, I have done 10k miles in the last 2 years and only first time since I had the car has it had the full treatment but it came up well, also car has been used in all weathers.
Only really dirty bit is the insides of the wire wheels, they need to come off for a really good clean, use a toothbrush on the spoke area but hey, the sun came out and the lure of the open road left all such thoughts in the garage