Often, hiring an attorney to represent you in your work comp ("WC") claim will be beneficial. An experienced lawyer will understand the system and be familiar with local insurance companies, doctors, and administrative law judges. An attorney can help an injured worker understand benefit categories and the time frames involved in getting these benefits. The California WC system is extremely complicated, and it helps to have a knowledgable person on your side.
Sometimes, however, having an attorney can actually be a hinderance. After you retain an attorney, they get 12-15% of your benefits. The attorney's fee percentage is set by statute. Fifteen percent is not a lot. For example, attorneys usually get 40% of a personal injury tort award. What this means is that your attorney can not afford to spend a lot of time discussing your case with you. Injured workers often get frustrated at the low level of customer service that their work comp attorneys provide. It is not that the attorney is not doing her work - it is just that most of the work is behind-the-scenes (writing letters, requesting medical records, rating reports).
To make matters worse, after you get an attorney, the insurance adjustor that is handeling your claim can no longer discuss your case with you. She can only contact and answer questions from your attorney. This is very frustrating to those who can not get frequent updates from their attorney.
Another reason you might not want to have an attorney is that if you are "unlitigated" an Administrative Law Judge has to review your permanent disability settlement. ALJ's are often more lenient to people who do not have lawyers when they have to mediate between you and the insurer.
Not having a lawyer can be a real disadvantage, however, because it will be just you against the insurance company (and your employer). Insurance companies are tough, and if you do not understand their role and mode of operation, you are at an extreme disadvantage. If you decide to forego legal advice, you should get a book about California WC law (Nolo puts out a current book), and read blogs like this one to educate yourself about the system.
There is another choice - filing "pro se" (sometimes called "pro per"). These Latin phrases just mean that you are choosing to represent yourself. There is a difference between not having an attorney and being pro se. You have to request a form from the insurance adjuster or file something with the WCAB to be considered formally pro se. The advantage of filing pro se is that you will be "served" with all of the medical records, reports, and coorespondence entering your file (as it would be served on your attorney if you had one). "Served" just means the reports will be mailed to you at your address. If you are not going to hire a lawyer, I highly recommend filing pro se so that you get a copy of everything that goes to the insurer. At least you will know what information they have on file.
In conclusion, it is possible to represent yourself in your work comp claim. Representing yourself will be less frustrating if you file pro se. Most of the time, however, retaining an attorney will be your best choice. Adjustors deal with attorneys differently than they do injured workers. California work comp law is complex - it is based on both statutory and case law that the average injured worker will be unable to locate or comprehend. The way the insurance company operates is difficult for an "outsider" to discern.
When looking for an attorney, make sure you select an attorney who specializes in work comp law. An attorney who has worked for an insurance company will be a powerful ally.