The typical contingent rate is one third of the money recovered for the client.
The contingent fee system gives the attorney the incentive to obtain the largest possible recovery for the client. The larger the recovery, the larger the attorney fee.
Of course, attorneys who handle personal injury cases on a contingent fee basis must screen cases carefully. If the attorney accepts a case where proof of liability or damages is lacking, he may work hundreds of hours and not get paid for his work. It is also a disservice to an injured person for an attorney to create false hopes of a successful outcome if that is not a realistic possibility.