For personal injury lawsuits in Ontario, Canada, the time you have to sue is generally two years from when you suffer the injury. This can also be true in malpractice cases, if it is very obvious that the professional did something wrong, and that your injury and damage resulted from the mistake.
For most professional malpractice cases, though, the lawyer must investigate before suing to find out whether or not the professional actually made a mistake in the first place. The law allows for a reasonable period for you or your lawyer to investigate the case and see if a mistake was made.
In cases where the injured person did not realize he or she was injured for some period of time, the law will add the two years you have to the period of time you did not realize you were injured. For example, if you had medical treatment, and found out a year later that you suffered injury during the medical treatment, then you would still be allowed two years from the date you discovered you were injured, to bring your case.
If you have been injured or suffered damage because a professional made a mistake, write out the timeline applicable to your particular case and consult a lawyer in your area to see if you still have the right to sue the person you feel was responsible.

