What are the principles of mitigation of damages in a personal injury action?

In Karas v. Rowlett, 1943 CanLII 53 (SCC), [1943] S.C.J. No. 46, Rand J. explained these principles of mitigation of damages at paras. 8-10: It is well settled that the person who has suffered from such a wrong is entitled, the far as money can do it, to be placed in as good a position as if the contract had been performed. With this there is the parallel duty on his part to take all reasonable measures to mitigate the loss consequent upon the breach. The latter rule has been dealt with in a number of clarifying decisions, and the considerations to be taken into account are now well settled: [citations omitted]. Under the rules so enunciated, the steps which ought to be taken by an injured party must arise out of the consequences of the default and be within the scope of what would be considered reasonable and prudent action. There are obviously limitations to the class of venture, for instance, in respect of which the duty would arise, but, where there has been an actual performance within those consequences, whether or not within the duty, the benefit derived must be taken into account. When, however, it is a question of future action, we must keep in mind that the limitation to be put upon that duty towards undertakings involving more than ordinary risks and have regard to the fact that losses might be suffered which could not be added to the burden of the wrongdoer. It is settled, also, that the performance in mitigation and that provided or contemplated under the original contract must be mutually exclusive, and the mitigation, in that sense, a substitute for the other. Stated from another point of view, by the default or wrong there is released a capacity to work or to earn. That capacity becomes an asset in the hands of the injured party, and he is held to a reasonable employment of it in the course of events flowing from the breach.