What does the "duty to mitigate" damages mean?

I got a call from a potential client who said, "The insurance adjuster says I have a duty to mitigate my damages.  What does that mean?"  Simply put, that means you just can't sit around after an accident and let your damages get out of control.  Your damages include your rental bills, your lost earnings, your doctor bills, etc.  You have to "mitigate" your damages which means you have to make sure you do what you can to keep your damages reasonable. 

For example, if the insurance company pays you for the total loss of your car, you can't just keep renting a car forever and expecting the other party to pay for it.  At some point, you have to go buy another car or make other arrangements.  If you don't have a car, you just can't stay home from work and say, "Oh well, I don't have a car so I won't go to work for 3 months.  I guess they'll pay me for my lost earnings."  You need to get to work by making other arrangements when available.  If you truly cannot get to work any other way, then I suppose you will make your argument when the time comes.  However, you need to make an effort to keep your damages in check. 

If a doctor tells you to rest and not do anything strenuous, you should not go to the gym and reinjure yourself!  You can't hold the other party responsible for things they cannot control or for mistakes in judgment on your part. Therefore, generally speaking, you have to do what you can to keep your bills reasonable.  Of course, certain things are out of your control, but don't be surprised if the other party asserts you need to mitigate your damages.