Open Question: How much money do you have left to spend when you're a doctor?

when you're a doctor you earn quite a lot of money. let's say first year of being qualified you live in london and have a student loan, mortgage on a house and then the bills. you pay £10 a month to charity and you have to buy food for youself and furnish the building. how much would you have left approx per month to spend on clothes and stuff like make up and other things. what about if you rented an appartment in london with someone else, would htere be a big difference? don't judge, i want to be a doctor because i want to help people but you have to face the fact you earn a lot.