i use the wash gun every time...if the car is not to dirty i dont even bring out the bucket...i just spray the mitt i am using with the foam gun to get the build up out of it...
I don't know how I used to wash as many cars as I did w/o my new PW foam gun. One day Justin will listen and bite the bullet and get his. Its the own way to go. You use alot less soap and reduce the risk of marring significantly.