Well, first it depends on what level one enters. If one enters the seminary at the collegiate level, then it would be four years of college seminary. After that, depending on the seminary or the diocese, it's usually three or four years. In some cases, it's four years including a "pastoral year" outside the seminary in a parish setting, which is followed by deaconal ordination. In other cases, the deacon year is considered the "pastoral year."
In my own case, because the diocese for which I was ordained didn't have a seminary of it's own, I completed all four years of post-graduate formation and was put into a parish for a year, the last five months of which were spent as a deacon; so I was only a deacon for five months.
The priesthood has wrongly become a sanctuary for homosexual men. Some of them have never revealed, even to their families, the sexual struggles that they have endured for acceptance and love from other men. And that real need for homosexual affection can cause of lot of thirst for, and expectations from, the other men in the rectory - even if there is nothing physical intended. Other gay priests have wrongly received the full support and approval of those who see the priesthood as the ideal life for them to live, believing that this life, lived under the cover of celibacy, will protect them from the scandal and questions and complications of living out in the real world.
I recently talked with a very good Catholic mother whose son is homosexual and who has struggled for years with many quick, abusive and for-the-most-part secret relationships with other homosexual men. She says he is scared to death that he will become "known" at his job, and suffer the consequences of not being accepted by his co-workers, and ruining any chances of advancement in his career.
I asked her, as a consequence, if she ever wanted her son, who is a good catholic, to become a priest so that he could avoid the scandals, the rumors, the questions of non-marriage, the fears of “career” advancement?
"Heaven's no! He would just be living a lie, and as a priest no less. He would be forced to live a double life, within himself, with God - as His representative, and with the people he serves who would never know his true self."
She is an exception.
This document will do very little to stop the homosexual infiltration of the Church. And, until there is a full, public, clear and papal teaching about the morality of this issue, and until there is a canon law prohibiting the ordination of homosexual men which is supported by severe penalties for those who would violate that law, then there is nothing that anyone can really utilize in their earnest and conscientious attempts to stop those homosexual men who are already ordained, and who hold positions of power and authority in our Church. Those men will simply ignore this instruction.