I'm not really prepared to say what my best day has been
But every Monday I now do a minimum of £220.
Other days of the week can vary between £20 and..er... a bit more

Yesterday for instance was £150. And that was £38 commercial and the rest Domestic.
Today it will only be about a ton as I have to finish at lunchtime.
Tomorrow will be good as I'll be making the effort to squeeze as much of Friday's work into it as I can....due to friday being a bank hol of course....well...it could be good, but as a result of having to work in certain Commercial work that would be done on the Friday, it will get in the way (because of location and necessary timing) it will get in the way of my residential stuff, which could well mean that I'll struggle to do much more than a ton.
Once a month I have a really good day, and once overy 8 weeks I have a really good day
But I've also been going 23 years, I'm ENTITLED to be earning decent bloody money at last!
And it is only in the past 3 years that my income has began to grow, and it's only been since Christmas that things have really fallen into place (due to a little re-organising).
For anyone thinking of window cleaning, I would say that it is a reasonable aim to expect to be able to earn an income of about £13-15,000 per year, add on 5k to that for your business costs.
But don't expect to hit £20,000 turnover for a few years! (15k income)
It takes quite a long time to build and consolidate a window cleaning round!!
Ian