Legal Question in Real Estate Law in California

All this is a matter of private contract, subject only to some rather general limitations upon the terms of attorney-client agreements. I would say that in most representations, the attorney or her/his firm has a duty to keep charges and billings in line with what a client might reasonably expect, and to pre-inform the client when it becomes necessary to incur unexpectedly large expenses for fees and/or expenses (such as expert witnesses, etc. On the other hand, the specific situation you mention -- exhausting a retainer and billing additional fees or expenses -- is not at all unusual, especially where the retainer is modest in relation to the likely costs of the case. My retainer requests, for example, are often scaled to cover only the initial costs of learning about the client's legal problems, preparing the initial document(s) (demand letter, complaint, answer, etc.), and the other costs of the first month or month and a half of the representation. My representation agreements make it clear that after the initial chores are done and the retainer becomes exhausted, I will bill on-going fees and costs monthly, in arrears. A retainer is not a quotation to handle a case from start to finish. It is a good-faith down payment (at least usually).

Read the terms of the written Retainer Agreement; they determine the rights and responsibilities of the attorney and client.