Chaye,
you set your ground rules? yes be firm and show her you are the no-nonsense kind, she'll probably be more careful with what she do. My maid when 1st came, ask for a lot of things, imagine she give me a list of things to buy for her (toiletries , body lotion, deoderant..etc etc etc ) i just simply tell her, i'm not paying for this and that and this and that and will deduct from your pay. Thereafter she only dare to ask for the necessities cos she complain that they are expensive in Singapore.