Is it okay to respond with a smart-arse comment to that?
I wasn't asking how to do a 1st clean or how to clean a window - kinda irrelevant really
You did say you where running out of water, that's a tip on how to save it similar to the trad comments that you didn't mind, so would say its relevant.
But seriously somebody pointing out something you already know isn't anything to get upset over, the same could be said about not charging enough to cover 10 minutes work.
Just up your prices in six months to cover the shortfall and take the shortterm hit for the sake of a professional image.