There is no rule that says you must hire an accident attorney. Doing so is more a decision that you make based on your willingness to deal with the hassle and speculation of whether it is economically beneficial to you. Although any firms that handle this type of law should do so on a contingency fee basis (meaning they only get paid if they are successful) it is entirely possible that some very minimal accidents with one or two trips to the doctor can be resolved with or without an attorney...