Had a one-off clean today, which sounded fairly straightforward - 7 windows (with secondary glazing), in & out, all ground floor. Turn up and the windows are fairly large Georgian sash windows, with 2 panel secondary glazing. It took 6 hours! Absolutely filthy - apparently the windows hadn't been cleaned in 15 years, with the secondary glazing staying in place all that time as well. Couldn't even blast them with the brush, as paintwork flaking & gaps you could put your finger through. And to top it all, had to work in the rain/sleet.