This all takes me back to my days up and down a ladder, long before WFP was so much as a glimmer in a lab technician's eye.
In those days, if you'd used terms like 'maintenance cleans' and 'traditional' you'd have been laughed off the streets. 'Traditional' meant leather and scrim, many still scorned 'new fangled' squeegees!
But this issue of time existed back then - many a customer complained I'd only been there for a few minutes. My choice of method (like most shiners then) was damp scrim. Properly washed and wrung out, it would remove dirt and polish all in one operation without smearing. All it needed was practice and elbow grease.
If I got a complaint I would challenge the customer to show me where the problem was - they never could, the glass always shone spotless. Then I would tell them that how I did it and how long it took was my business, the quality of the job was theirs, that's what they paid for.
I'd finish up by saying: "I'll rub 'em with the top of my head if I feel like it, provided they're clean when I finish I've done what I've promised and you've got what you asked for, now you have to pay me!
The bottom line is you are selling a service which renders the glass/sills/frames etc perfectly clean. You are selling a result, not providing an hour or so of entertainment. Provided the end result is achieved, how you achieve it and how long it takes is immaterial.
