If your lawyer does not suggest a written agreement, you should. If your lawyer does not prepare a written agreement for you to review, then you should submit one to him or her. The Model Professional Rules of Conduct for the legal profession recommend that new clients be advised, preferably in writing, about the basis or rate of legal fees within a reasonable time after the law firm begins to represent them. Many states have more stringent requirements. For example, the state of New Jersey requires that the basis or rate of the fee be put in writing and if the services are for personal, family or household purposes, the agreement must be written in plain language.
All states have some rules that regulate contingent fee arrangements.
Contingency fees are often limited in personal injury cases, and often in medical malpractice suits. These limits vary widely. However, it is rare to see contingent fees in any case in excess of one third of the total recovery. Some lawyers may suggest that these very laws dictate how much they must charge. This is not true.