[leapstallbuildings]

I would agree with it depending on how you get the custies.  I get most of mine from YP or personal referrals.  YP users normally say if it's just a one off (usually end of tenancy clean) so I've no problem bumping up the price for those.
Apart from those who tell you from the start that it's a one off, I reckon I probably lose or dump about 1 in 5 during the first few months to a year.  This is a very small number though because the overwhelming bulk of my round is well established.

[Sunshine/Cleaning]

I've been window cleaning since Tosh had a full set of teeth, so that's quite a while.

My drop rate is minimal prob less than 5%. When I get new customers they generally all stay as regular customers.

I would say that for newer cleaners the drop rate would be higher so expect a 25% drop, as you say, after the novelty has gone.

If this is the case, you have to try and discern the quality customers, that will come with time.

I have very few customers that I started with, as I didn't have much clue as to pricing, plus you tend to get the chaff anyway.

keep turning over the customers and only keep the "diamonds"