My Mum always said, when were living at home and earning a fulltime wage, that 1/3 to spend, 1/3 for rent and 1/3 to save was a good balance. It always seemed like too much to be paying M&D in rent, to me, but now that I am older and have a much better idea of the true cost of living, I think it was very reasonable.

I think you are fantastic for taking on a teenager. Bless you all.