Whenever I take on a new client, I tell them I welcome feedback, as long at it is said politely. I explain to them that regular cleaning of a home is a process, by where I get to understand how THEY see their home. (Which may not be how I see their home!) This has worked out fine for me. Most people have no complaints. A few do, and almost always, its those types who end up nit-picking about everything, and I end up dropping them. Most people appreciate a job well done, and really like it when the cleaner has a positive attitude (this sets the tone for the future relationship.) There will always be a few people who are just never satisfied, no matter what you do, and you just have to learn to shrug it off.
I had a new client last year who has white, shiny floor tiles. Her house was pretty dirty - she was elderly with an ill husband and a dog. Well, I cleaned the HECK out of her home, and I was feeling SO proud of what I got done. Those floors just sparkled, they were so clean! All the dust was gone, everything had been cleaned. As I was wrapping things up, the lady came to me and said "I dont think this is going to work with you." I asked "Why?" She said "Because you didnt use BLEACH on my floors! I always use bleach!" Well. Number one, thats an awful thing to use on good tile floors, and number 2, it isnt safe for you to do! I explained that to her gently but she remained adamant. I took my pay and went home annoyed and frustrated. But after I thought about it, I had to laugh. As a nurse, I had many elderly patients, many of whom had some sort of dementia. This woman showed classic signs of that. And you cannot be angry at someone who honestly does not know what they are doing all the time. When she grew up, bleach WAS commonly used on many surfaces, because back then they didnt have the manufactured stuff we have now. Older folk often seem to think bleach will kill all germs and keep their homes safer (this just is not true!).