Hey all.
just another point about this. I have one custy who openly admits that she is the fussiest sod when it comes to cleaning etc. She was really sceptical when I first started cleaning her windows as to whether it would be good enough and was over keen on close inspection before and after drying. When I had the 28 TDS problem hers was one of the houses I had done; so with some trepidation I went round and explained what had happened and asked if there were any problem windows with spotting etc; she completely threw me by admitting that she didn't have a clue as she no longer checked - she was so impressed with the first few cleans that she felt no need to check on my work after that as she assumed the results would always be excellent.
I think many customers get into the mindset that you do a good job and pay up - similar to the barber showing you the back of your head with a mirror - how many of us actually take notice? I just nod and reach for me cash.
just thought that the above might explain why not many complaints are received for the odd time we forget and clean with a high TDS
Cheers, Tom