A percentage of customers have price first and foremost, these are the ones who undervalue your service, usually keep you waiting for payment and drop you is someone will do it 5p cheaper.
When doing some biz studies and projections I canvassed approx 500 houses and the order came out the same as h2o's list.
Also to back this up, when you canvass how many windows do you see that don't meet your standard of clean? Yet the potential custy will not change, why? When asked, the majority say, comes regular, been doing it for the last 5,10,15 years we trust him..
Even when they don't clean as good as I would like.
Quality seems to be down the list, and price off the bottom of the page.
A good brand helps overcome this, your vans are seen out and about, and over a couple of years you become part of the "furniture" and a member of the community leading to trust
Darran