Common mistakes in making the sacrifice
1. Some pilgrims appoint others as their agents to do the sacrifice on their behalf, and then they themselves proceed to do the other rituals while the agents go for doing the sacrifices. However, there is a problem since there is no coordination between the pilgrim and his agent: the pilgrim ends up doing the taqsir or halq and then takes off the ihram assuming that his agent has done the sacrifice, and later on finds out that the agent has not yet done the sacrifice. He should immediately remove the sewn clothes and refrain from the things forbidden in the state of ihram until the agent has done the sacrifice. After the sacrifice has been done in this case, then he can relieve himself from the restrictions of the ihram, and there is no need for him to repeat the taqsir.
2. It is important that the pilgrim should appoint someone as his agent who is experienced in this matter since the conditions required in the sacrificial animals cannot be ascertained except by those who are experts who know its requirements like the age of the animal, etc. So if the sacrifice is done and the pilgrim proceeds to the following rituals and later on finds out that the sacrificial animal was underage––if he finds out before the 13th of Dhul Hijja, then he must redo the sacrifice and then there is no penalty on him. One should know that those who do the slaughtering are many and they do not neglect in helping those who need their help.