When you bring a lawsuit seeking compensation for injuries caused by someone's carelessness, you must prove to the court what your life expectancy will be for the foreseeable future.
Reason: The jury is asked to make an award to compensate you for injuries that you can expect to have for the rest of your life. They are required to determine for how many years into the future the award is for.
The life expectancy tables are based on statistical averages, also known as actuarial tables. Obviously, they do not apply to every single person's individual scenario.
However, if your injury is permanently disabling and will affect you for the rest of your life, it is critical to determine how long you can be expected to live so the jury can adequately award you compensation for the duration of your lifetime.