You should be paying your fair share of expenses.
Rob's roommate Tim asks him for his share of the monthly rent, but Rob is short by a few hundred dollars.
Rob wants the rent to be paid.
Rob puts in extra hours at work and cuts back on spending, so he can pay his share of rent.
Rob refuses and tells Tim to pay for the entire month's rent himself.
The rent is paid and Rob continues to live happily in the apartment.
Rob is kicked out of the apartment for not paying rent.