I have never hired a house cleaner, but getting to the point that I need to. I am 82 and I have a very bad back, and can do very little housework. Can't stand up but a few minutes at a time. (I can handle sewing very well though), until the sciatic pain kicks in. What is considered a fair hourly wage for a cleaner? Or is it better to pay by the job, and not by the hour?