Beware of the double openers above a large single pane of glass,.. when I first switched to WFP i did really good, except for these! They take a few cleans before they're easy to do,.. but until they come right, clean the top 2 openers and then go away and do another couple of windows before you come back to clean the bottom pane,..
Most custies won't be home or won't ask, so don't tell them,.. carry on like its normal. If you cause a fuss, they'll go looking for marks,..say nothing & they might not notice!
Those that do ask,.. present it like its something that you've wanted for a long time because its BETTER, and now you've finally been able to afford it (emphasise that it cost a fortune!). Mention health and safety as a fringe benefit, but the customer wants to know why its better for them, not why its better for you!