How much for board and lodgings?

[WillIEverBeASizeTen]

Not sure if this is the right area to post, but here goes..

I'm a LP and do not earn a fortune. Have a DD21 and DS13. DD is working contractually part time, but makes up to full time with overtime. She has tried to go full time but they won't give her the hours contractually.

BTW, this isn't about her job, it's about the amount she should pay me monthly. She earns on average £800 per month, but that can sometimes be £1000ish too. Currently she pays £120 per month.

Question : Enough or not? (The only commitment she has is her car insurance)

£100 a month for food according to pils who have just worked out feeding an extra adult. you also need to add electricity, water, gas, tv licence, council tax etc.

I paid more than that as a student 20 years ago, so I doubt it is enough.

how can it be 20 years ago?

25% of her monthly wage - if she makes it up, then she needs to pay more to help with the running costs of her own home.

We worked on the principle of 1/3 of net wage for everything except phone, which was extra (all calls itemised, sounds picky but only paid for personal use). Now DD1 is 26, living away from home and managing brilliantly with money. She can even save a little bit of money and that's with a 3 year old and all household bills.