who is to say you cant deliver a first class service at speed.
I would say the biggest efficiency i have introduced is to use a extreme brush with pencil jets( i was always a fan man)
and to change the the way i now clean
i spend less time on the glass, less rinsing and have knocked off 5 mins per house on average, i am earning more and finishing earlier, all regular cleans and there is no difference in the finish than if i spent more time scrubbing and rinsing
Once its clean its clean
Im sure other things such has having a brush in good condition ( i change every three months) having the round organised helps.