We want to be very careful here. It is true that the celebration of the sacraments are central to the priesthood, they are not central to every priest. Many priests never celebrate sacraments other than mass. The Church does not want them to do so. They have another calling. I’ll offer a few examples.
Hermits and monks: They celebrate community mass, when the superior grants them permission to do so. They never celebrate any other sacrament. Once in a while, they may be assigned as the confessor to the community. Obviously, if one of their own is dying and the superior is not available to administer Anointing of the sick, any hermit or monk who is a priest should step in and do it.
Friars: certain orders of friars are brotherhoods. The deliberately avoid distinctions between the ordained friars and the lay friars to the point that if there are more than two ordained friars in a house, only one can celebrate mass. The other must attend mass with the lay friars. There is on private mass that he can say. It’s not allowed. Unless he’s assigned to a ministry that requires the celebration of other sacraments, he may spend his entire life and never celebrate other sacraments or at most, he may hear confessions.
Teachers, scholars, administrators and even some bishops: many of these men have never worked in a situation where they’re expected to celebrate sacraments. They celebrate mass and maybe hear an occasional confession, but their priestly work is to preach, teach, administer or be bishop. Our own Pope Benedict was a parish priest for a very short time. He was a diocesan bishop for an equally short time. Father Ratzinger was a teacher and a world lecturer and consultant. Bl. John Paul was a youth minister for many many years. He did very little parish work. Bl. John XXIII was a history professor. Pope Paul VI was a lawyer.
Some of these men have never celebrated anything other than mass or may have celebrated other sacraments in special occasions, but not as a regular thing. It was not their ministry.
We have a young brother in my community who was ordained three years ago and he has never baptized, witnessed a wedding, buried anyone, administered the last rites or even done a May crowning. He helps out in a parish on Saturdays and Sundays where he celebrates one mass and hears confessions. The rest of the week his the Go To Guy for our pregnancy centers.
Then we have non-ordained friars who are spiritual directors, retreat masters, teachers, theologians, administrators and marriage counselors. Brother simply has a gift that none of us has. He is the kind of man who can fix anything. He is happiest when he’s alone with the brothers. He feels very uncomfortable around lay people. He says they make him nervous. He is an excellent writer and does a lot of theological articles and a lot of research when he’s not pulling something apart. The Secular Franciscans love him, because he helps with their formation and he’s an excellent moral theologian. Once a month, he attends their formation classes. People love going to confession to him, on those Saturdays when he is available. Because he’s not attached to a parish, he never goes to a hospital or a nursing home. He never does spiritual direction, though he says that he has no clue how to do spiritual direction, because he was never trained to do it. Most people are not trained for it, but many people simply have a natural gift and do it very well.
Can you imagine a Carthusian monk trying to do a Baptism? He wouldn’t know where to start. Imagine an ordained Trappist (not all of them are priests) leading a Holy Hour. He’d need a guide. They just don’t do these things. I can’t imagine Pope Benedict doing a funeral or a wedding. He would probably have to read it several times before. Prior to Pope John Paul’s funeral, I wonder how many years it had been since he had a funeral mass.

The man spent 25 years in an office and before that I don’t know how many years in a classroom, as a consultant or on the lecture circuit.
The point is that not every priest celebrates sacraments. This is the most important part of the life of a priest, but that term “priest” is used in the collective sense. It is not the same for every priest. Some priests are not called to that. It’s not their vocation.
Fraternally,
Br. JR, OSF