Well Dai, if it was just this month I would say it had something to do with bills ect. Who knows it may well be that?
I have a pretty good book on running a business and I turn to it from time to time, it has this to say on summing up about customer retention.
"Gaining the loyalty and trust of your customers can only be achieved if they feel you are fulfilling their exact needs, and that they will continue to receive value from you that meets their needs in the future"
it then goes on to say about how you should keep repeating your unique selling point to them as often as possible which should make it more difficult for them to leave. It says that if you fail to state your selling points strongly enough it is the reason they are likely to leave.
Above all never let them forget why they bought from you in the first place.
One long standing customer cancelled today. He said that the windows were getting dirty so soon after they had been cleaned, it wasn't worth having them done.
Ok so lets assume he was shooting from the hip and telling you exactly how he felt. How can we stop this sort of behaviour in the future? Well lets look back at the golden rule of customer retention...
"Above all never let them forget why they bought from you in the first place"
Something that I would try, it might not work but it would solve this problem a bit I think...
Produce a new leaflet, on it have a before and after. Something like "Not cleaned for 12 months" and "Just xx mins later, nice and clean"
I would then hand these out to customers, maybe on some sort of newsletter, maybe even ask them what they think of your new flyer. Hey if you really felt brave you could ask them to come up with a caption for your new flyer and offer a free clean to the winner.
The main aim is to try and drum it back into their heads, that no matter how bad the weather they do not want their house looking like the "before" photo. I think some people forget how bad windows and frames can look after 12 months.
Remind them.