I wash in 4 sections for every other wash or so.
I only do it because when I don't section, I tend to only get my HAIR clean and not my scalp, especially in the crown area.
Doing it in sections helps me really get to my scalp and keep it clean and buildup free.
I just section it with clips before jumping in the shower and start with the back sections first.
My scalp has been better since doing it this way.