I once paid for a spring clean to my tiny two bed flat, when my flatmate was ill. I was had. It was no cleaner than if I'd cleaned it. Not even the skirting boards were cleaned
However, when I lived abroad I had a cleaner once a fortnight. she was amazing. I never had any dust, the windows were always sparkling. I miss my cleaner! All she did was three hours once a fortnight. I could spend that long each week and not have such a clean house.