Got children? Nephews, nieces, grandchildren that are teenagers upwards? Even the missus (!)
Interesting things I have found. During the college summer hols (July/August) daughter has been working with me one day a week for £50.
I do about 40% more than I normally would and use less water per house! She more than covers her costs.
Modus operandi.
She cleans all the downstairs cills ahead of me (so I'm not blasting grit out of the bottom of patio doors etc) and gets the spiders nests out of the way and wipes the joint between the upper frame and the glass.
She also (damp scrim/dry scrim) buffs windows in wooden front doors and small side panels. If the custy is not in she will write out the payment slip while I reel in the hose etc.
I also get help de-snagging hoses too.
Once she becomes proficient then maybe a bit of blading the odd downstairs window to fill her time.
Also, if I want more custies I get her to knock on a couple of doors either side while I work.
Very useful on a conservatory clean as all the muck and grit on the sides is being done while I do the roof. And of course conservatory cleans are "extra money" which makes it more self funding.