That's the question Chicago asks in the song of the same name on their classic 1969 debut album, Chicago Transit Authority (here's a link to the original version before it was shortened for radio play). When it comes to the deadlines for bringing legal claims, not knowing the time will indeed give you "time enough to cry." That's because the law sets deadlines, called statutes of limitation, by which legal claims must be pursued. If those deadlines are missed, the claim can no longer be made in court, no matter how strong the facts and law may be to support it.
If you suffer a personal injury in a car accident or other event that is someone else's fault, you may be entitled to compensation. Immediately following the accident is not the time to accept a personal injury settlement. This is especially true if you are still treating for your injuries, or if the full nature and extent of your injuries is not yet known. Typically a personal injury settlement will be a one-time payment, and the insurance company or the party who caused your injuries will demand that you sign a release in exchange for the payment.