The length of time it takes for each case to settle depends entirely on the facts of each case. It is difficult to answer this question at the beginning of a case because so many facts are unknown. It will depend on the type of injury, the delay in obtaining documents and expert reports, the degree and extent of the injury, wether the insurance company and adjuster wish to settle and the period of time it takes for the injured person to recover from the injuries.
It is no surprise that what you and your lawyer thinks is a reasonable assessment of the value of the claim and what the insurance company assesses it to be, is often quite different. This difference of opinion causes some delay and sometimes, in order to have the insurance company provide reasonable numbers for settlement, a court action must be commenced. Sometimes, a claim in court must be commenced in order to meet a time period such as a statute of limitations [every case has a time period by which you must start a court action or otherwise give up your tight to sue].
From commencement of a court action to trial, it takes about 12 to 36 months on average, depending on a variety of factors, some of which we mention above. If court action is not required, the usual time period for usual injuries from time of incident to settlement is about 8 to 24 months. The timing of settlement usually depends on when you have recovered from your injuries. It makes no sense to settle before the full extent of your injuries are known, including knowing the long term consequences of the injuries.
Once your injuries are fully known and you obtain [we do this for you]an opinion from a medical expert [or experts] stating that your injuries will not get any better or worse, you can consider settlement.
Keep in mind that there are some types of cases in which insurance companies are reluctant to settle, such as professional negligence, medical malpractice and products liability cases. You usually have to sue to recover in these cases.