I’m not sure I’d go with 1/3. Although that was my mums suggestion many decades ago. I was amused by it as she made assumptions about my earnings and was way off the mark and it was a lot less than she expected.
It is a tricky one. A friend has 2 working kids. One is on 65k the other is on min wage. Not sure what you do there. The one on min wage will just about manage expenses relating to work and a bit of a social life.
They don’t need the money in the household. But will look for something.
