This is an depate that can go on for ages - but here is the simple truth - it down to personal preference.
However my personal preference in washing the car is:-
Citrus prewash - dwell for 3 minutes
Chemical guys No Touch Snow Foam - dwell for 10 minutes
JET WASH OFF
and that's it for the winter months - gets 95% clean
If you have stubborn marks do stage two again.