"Surely it should be based on what’s it actually costs you for them to live there rather than how much they earn? Otherwise you’re just profiting from your children."
This ALWAYS comes up on such threads, usually posted by people with no idea how much it costs to keep an adult child!
Usually the amount requested by parents is WAY below what it's actually costing them to have that person living there!
How much do you think it costs the op to keep them in food alone? Because 18 year old men eat a lot!
I'll tell you right now I have an almost 18 year old daughter and she eats more than £25 of food a week!
Then there's other groceries (cleaning products, toiletries, occasional necessities like lightbulbs & batteries), gas, electric, water (in England & Wales), Internet, any tv packages that op gets that they use, possibly even elements that op wouldn't have if they weren't there.
op is also paying more in rent/mortgage and council tax due to having a larger property to accommodate them. It can be argued if they moved out she could downsize to a 2 bed property for just her and dd.
Council tax - as one of them is working full time she'll have lost her single occupancy discount too BECAUSE as far as govts concerned that adult (ft working twin) should be paying half the council tax - bet that's not cheap either! Based on even CHEAPEST council tax where I live that's £93 a month - £21.43 a week - alone!
So... A rough estimate of op's outgoings based on my own + local 4 bed property costs (and hers are likely higher with 4 in her house) and adjusting for 4 people:
Rent/mortgage £825
Council tax £93
Groceries £500
Gas £125
Elec £100 (winter rates admittedly)
Internet £25
Tv licence £12
Total £1680
And I reckon that's actually a pretty conservative estimate as I live in a cheap area and am on a tight budget myself.
That means it costs £420 per person per month.
Other posters on this thread - what do your bills actually cost? Does what the op's ft son is asked to pay even come close to your per person minimum necessity costs?
I think some are being quite head in the sand about what this is costing op or indeed what supporting their own full time working adult child is costing them.