"For instance, if you have a candidate who's coming right out of high school or right out of college and going into seminary, you've spent most of your life in class. And...you tend to have an expectation of seminary as more classes. Then you get to seminary and most of your time is actually spent on academics," Mayer said.
"So it's very possible to just see your preparation for the priesthood as being primarily a mental exercise, something that you're still competing with others for the best grade. The seminary just becomes in the stream of everything else you've done, which is primarily, for Americans, school."
Mayer said men in spirituality year still take classes on things like the Catechism of the Catholic Church, and they read some spiritual classics, like "Story of a Soul" by St. Therese of Lisieux and "Confessions" by St. Augustine.
"You're going to have some classes, but they're actually just for you, they're just for your sake, for the sake of your flock," he said.
Another important goal of the spirituality year is to help men with their human formation by providing ample opportunities to meet with psychological counselors, and to examine their own weaknesses and shortcomings.
"There's a surprising amount of human formation issues that a spiritual bandaid cannot fix," said Fr. Brady Wagner, who serves as the director of the spirituality year for St. John Vianney in Denver.
"I think doing a Spirituality Year or a propadeutic year gives men opportunities to really seriously consider their history, their life, their own experiences in light of Christ and find some freedom," he said. "And if a guy is not free, then he's able to see that, okay, this is probably not going to be a good fit."
Wagner added that most men throughout the course of the year take advantage of the psychological counselors that are available to them, and even if they don't engage in formal therapy, almost all of them receive some kind of growth counseling.
"It really is...having to get foundation in a life of prayer and having done some good work in terms of healing. Maybe there's some things that I've suffered in my life, in my past experiences. (Seminarians can) have them healed and integrated into their lives according to God's providence," he said.
It helps seminarians come to a deeper recognition that God has "been with me my whole life, and I know what it means to walk with him."
This spiritual and psychological work allows men to enter into the rest of the seminary with as free of a heart as possible, Wagner said, or to discern that their call is elsewhere - either somewhere else in religious life, such as the monastery, or to marriage.
"There is a heavy emphasis on vocational discernment, but only after having sensed the truth of my baptismal dignity and identity," he said, which "naturally opens up vocation becoming clear. And so I think a lot of guys really have a sense of clarity by the end of the 30-day spiritual exercises. They have some clarity about their vocational discernment because the exercises themselves really have an orientation towards making an election to a state of life."
Because spirituality year has a heavy emphasis on discernment, there are often men who choose to leave seminary during that year, Wagner added.
"It's not uncommon, where guys leave throughout the year. We just had a guy after his three-day retreat, he had a deep sense of confirmation that the priesthood is not his call, and a lot of joy and a lot of freedom around that. So he just left recently and, and that's actually a good sign. A lot of guys go through that."
Mayer said spirituality year serves as a good "check" on men's motives and expectations for entering seminary.
"I've seen a lot of really beautiful things happen in spirituality year in both directions, from men deciding that this is not the call, but they're grateful for the time they were able to have, or men really hunkering down and realizing that this is where the Lord's leading them. Spirituality year is also really good for revealing deeper issues and wounds that we have," he said.
Mayer said he learned lessons during his spirituality year that he continues to carry with him in his priesthood.
"I think having nine months of being really privileged to live like that certainly helps us analyze the way that we live our lives, and helps us make choices to preserve those things that are most important, like prayer and relationship - relationship with God and relationship with other people," he said.
"Something like spirituality year, where you have an intensity of prayer and relationship and intensity of focus, you don't have all the distractions that you normally have to blame your issues on," he said.
This can sometimes bring up deeper issues that men may have been avoiding or that went unrecognized before entering seminary, Mayer added, like anxiety issues or other psychological problems.
"It's good for them to show up and reveal themselves and how deep they go, in a safe context and safe environment, rather than 15 years later at a parish, when you have a nervous breakdown or something," he said.
Overall, he said, he thinks things like a spirituality year or a propaedeutic experience lays a strong foundation for seminarians for further discernment.
"A lot of things are revealed when you spend a lot of time in prayer and sinking down into your heart."