Excellent post Ian Rochester. I go for a simpler version of what you suggested but it's very similar. The truth is it's much easier for the customer to make a decision if they, A) Know a little about who's standing at their door and get a good first impression, people like investing in people. B) get a minute or 2 to think about what you have just asked them and figure out if it's a viable option, not many people have window cleaning at the forefront of their minds and if they are asked to make a snap decision or feel under pressure to give an answer they will invariably say no. By talking a little more you give them time to think, the next stage being to ask if you could give them a quick quote, alot easier to agree to than a full on yes, then while you walk round their house they have even more time to get used to the idea, they also feel you are making a small investment on them by spending a few minutes quoting their house making it more likely for them to agree. TOP TIP: When actually telling them how much it will be, don't let their be a long pause while you see what they say etc, tell them the price as a part of other things they need to know such ways they can pay and how they pay if they are out, is there access etc. Act as tho they have already said yes almost. Then nail it by saying "I just need to take a few details from you" name, tel no, email etc and tell them when you wil next be cleaning their neighbours. Its rare people say no or I'l let you know once you've got that far.
TLC