I had one a while back. It's a 50 quid detached house which I clean whenever required by the customer. She phoned to say she had been quoted half of what I charge, but that because she is happy with the quality of my work, would rather keep me if I could match the lower quote.
I replied that I couldn't work for less than I quoted, and said that I would leave it with her to decide who she wanted to use.
A couple of months later, she rang me to clean them for her. I duly did so, and was paid my asking price of 50 quid (euro).
John.