If you lock the door but you are confused whether you have locked or not, and then from your work place you go back to check the door. During bath you use the tank water completely but you find yourself confused whether you are clean or not. If you are a tension patient and you are suffering by sorrows, if you lost your conscious for some time, If you are worried about something and it bothers you a lot then for relief recite                                 

with three times darood sharif before the recitation and after the recitation. (Tanveer Iqbal, Mulhwali)