If you have caused the damage that makes the repair necessary you might well have to pay for it. An example might be if you have blocked your WC with nappies. You may also be charged for repairs after you have moved out of your home. But you will not be charged because, say, a kitchen unit is old and has worn out.
Your Housing Officer will notify you as soon as possible that you will have to pay for a repair. If you think the charge is unfair or will have difficulty in paying it, you should discuss this with your Housing Officer.