Depending on the seriousness of the matter, our advice is to get a lawyer involved as early as possible, as frequently a lawyer can help you achieve the results that you want. This is particularly important in an accident case, as the other sides insurance company has far more information than you do, and may take advantage of you. We suggest that you look at the specific sections of Free Advice that deal with the type of accident or personal injury involved in your case.
Even in commercial disputes, getting a lawyer involved early can help the parties keep perspective so that a simple matter does not get blown up out of all proportion. A good lawyer can keep you from making concessions that would hurt your case if you can not amicably settle, prevent critical evidence from getting "lost", witnesses from changing their mind, and avoid conduct that can land you in trouble, or expose you to dangers you had not considered.