The best time to decide that a structured settlement is not right for you is before you consent to such a settlement. You may wish to press for a lump sum settlement, for periodic lump sum payments in addition to smaller annual payments, or for a lump sum to be issued at a future date when you anticipate a particular need. If you work out a settlement package that is in your best interest at the outset, you will be able to maximize the value of your settlement and get the greatest tax benefit from the structured portion of any settlement.
Remember that the companies which purchase structured settlements intend to profit from the purchase of your settlement. Their profit comes out of the payments you would otherwise receive.
Recall also that if your future earning capacity is impaired as a result of your injury, you should consider your future needs when you are making any decision regarding the sale of your settlement.