"the fact that the custy is in control of you from their perspective"
and Tosh's
"I only keep customers who want their windows cleaned at the frequency we originally agreed"
Personally I would be uneasy if I had a manager running my business and they were taking this approach.
I advertise cleans at a frequency to suit the customer, from one-offs right down to 2-weekly cleans.
I have structured the business such that I have several days off a month for bad weather and for the fact that I will lose X amount per year and some will drop off or reduce their frequency in the winter months. So far this year i've lost quite a few custies to the Grim Reaper, but have taken on more than i've lost on, so my projected turnover is the highest its ever been. I've lost one to "leave it till March" and a couple have gone from 4 weekly to 2 monthly. My business can cope with this quite easily.
If we have -20 for more than a few days, or lots of snow, or I get injured/ill that will be much more difficult to deal with financially.
As i've said before I see myself not so much as a window cleaner but in the customer service business - the customer is all important. I'm not saying sit back and let them sh*t on you, but deal with them as you'd want to be dealt with and you can't go wrong. I know i've said it before but I canvassed for 3 months in April 09 and have spent a tenner on advertising (parish mag for a year = 1 new custie). My stats show I've had 3 times as many people join me as a customer by word of mouth referral and being approached whilst working than I have by canvassing. If people are recommending you then you are doing it right. They are going to do that if you get "funny" with them (and i've had my fair share believe me).
I personally don't feel its fair (and am pretty sure it would fail the reasonableness test in a court) that a customer or service provider can't change the terms of the contract with reasonable notice. I always ask what frequency a customer wants and let them tell me. I can then price accordingly. In almost all circumstances I charge the same for an 8 weekly clean as a 4 weekly clean. If they then want to change frequency then i'm covered if its from 4 to 8. If they want to leave it over the winter in most cases its no then no problem - i'd lose, say £15 x 5 cleans = £75 at a time of the year when there is usually such poor weather and the days are so short it can be hard to get round - no big deal. If its a property that's gonna be filthy, then I tell them the first clean in March will be more.
As I say, i've only been going 3 1/2 years, but if i've lost more than 5 to this i'd be surprised.
People on here jump up and down wondering the best way to get new business, but it's easier to retain existing custies than to get a new one - you just have to structure your business correctly. You can then cope with the odd few winter drop offs.