I used my clay bar for the first time after shampoo this weekend. It took far more post wash dirt off than I expected, very impressed, I will buy a seco d o e for the top half now though and keep one for the dirtier tar dirtied lower half.
I then covered the car in Autoglym Super Resin polish which even by hand removed some swirls! I've been told to seal it with Autoglyms HD wax so will get some in for next time I get chance to te do the shampoo wash rinse clay SRP in maybe 3months
Time? Shouldn't need doing again till winter then