There is not a set litmus test for how long it takes injury cases to resolve. Like human beings, each case is unique. So from filing suit, to settlement or verdict will be different in every case.
In fact, some cases settle fast, while others cases can stretch out for many months or years. Many times it is up to the defendant's liability insurance company. Other times it's up to the victim's insurance carrier. But this usually depends on the insurance company you are dealing with.
Most insurance companies offer low ball payouts at first. They want to settle matter as fast and as cheaply as possible. In other words, you may get just pennies on the dollar as your first offer.
Getting what your case is really worth usually depends upon how much work you or your lawyer did to gather facts, and document evidence quickly.