You will hear many personal injury attorneys talking about how much your case is "worth". That phrasing is problematic as personal injury awards are meant to redress a harm and put a person back in the position they were prior to the injury. Thus, your personal injury case is "worth" what it takes to pay for your medical bills, fix your personal property and compensate you for any other losses you sustained (e.g., pain and suffering, lost wages, etc.).
Because these types of cases are often handled on a contingency basis, attorneys know that the more money an injured party receives, the more money the attorney will receive. In that sense, a personal injury case has great value for the attorney and might be the reason many of them talk about the "worth" of your case.
If you suffer damages because of the fault of another, the question you should start asking is, "how much will it take to put me back in the position I was before the accident?" Early in the process, you will find that this is a very difficult question to answer as medical bills are still being incurred, you may be unsure of your medical treatment going forward, and you may still be dealing with the immediate emotional aftermath of your injury. As time passes, your damages will become more clear. You will know the amount of your medical bills, you will know your medical prognosis and you will have time to consider the impact on your life. Once you know all of this, you can begin to put dollar figures on the amount it will take to compensate you for your injuries. Any attorney who claims to be able to tell you the "worth" of your case before you know any of this information is likely more concerned with their bottom line than with yours.