When can you receive the sacrament of Holy Orders?

The requirements to receive Holy Orders are covered in the Code of Canon Law, canons 1026 - 1054. You must receive the proper formation and be approved by the diocesan bishop or the competent superior. The candidate must have an integral faith, be motivated by a right intention, possess the required knowledge, and enjoy a good reputation, good morals, and proven virtues, and other physical and psychological qualities which are appropriate to the order to be received. The candidate (for the presbyterate) must have completed the age of twenty-five and possess sufficient maturity; there must have been a minimum of six months observed between the diaconate and the presbyterate. Candidates for the presbyterate can be promoted to the diaconate only after they have completed a five-year curriculum of philosophical and theological studies. He must have completed a trial period in pastoral care as a deacon. He must have been confirmed, and received a liturgical rite of admission. He must have received the ministries of lector and acolyte and to have exercised them for a suitable period. All those to be promoted to some order at to make a retreat for at least five days in a place and manner determined by the Ordinary, and confirmed by the same Ordinary that he has made such a retreat.