The Mass Effect franchise introduced dozens of sentient races to the galaxy, and the Quarian race is one of the most intriguing. A resilient humanoid race of nomads, the Quarians show a remarkable knack for technological understanding and survival. Unfortunately, their love of technology disrupted their lives when they created an Artificial Intelligence known as the Geth. Upon realizing the Geth would one day advance beyond and rise against their creators, the Quarians tried to exterminate their creations, which resulted in all-out war and exile from their home world, Rannoch.
Forced into one migrant fleet known as the Flotilla, each member of Quarian society must make themselves useful in order to keep the entire fleet functioning and alive. This drive toward personal responsibility pushes young Quarians to leave the Fleet when they come of age and embark on a journey of self-discovery in an effort to find something remarkable and valuable to bring back to the Flotilla and gift to the captain of the ship they wish to join.
When Commander Shepard first met Tali'Zorah on the Citadel, she was on her Pilgrimage, and it was from her that Shepard first learned about Quarian culture and society. Through Tali, Shepard discovered how important it was for a Quarian to ensure their usefulness by starting with their contribution to the ship they wished to serve upon returning from Pilgrimage. Many Quarians return to the Fleet with food, fuel, valuable technology or rare salvaged ship parts designed to improve the function of their systems, which they've worked hard to maintain for centuries. The very lucky few will bring a new starship to add to the Fleet, increasing both their living space and their power as a unit.
The Pilgrimage is also an effort to maintain genetic diversity among the fleet, encouraging young Quarians to find and make a life among a new crew, rather than staying close to home and risking population issues. Maintaining the population of the Flotilla is a delicate balance. Ensuring there is enough genetic diversity to sustain their entire race is a priority, especially if they wish to one day return to Rannoch and reclaim their home.
Due to their nomadic nature, many alien races see the Quarians as scavengers. Because they tend to keep to themselves, closely guarding their Flotilla and avoiding other alien cultures as best they can, it's a little-known fact that young Quarians on Pilgrimage are often a bit naïve to the ways of the galaxy. This naivete often gets them into trouble, as others perceive them to be gullible and tend to take advantage of them. When Shepard met Tali, she'd been forced to seek protection from the Shadow Broker because of valuable information she found that could prove Saren's crimes to the Council, but she was conned and nearly killed by Saren's men.
Shepard met many a Quarian on Pilgrimage in their travels, including a young man on Omega named Kenn. Kenn got trapped on Omega after opening a shop and being forced by an Elcor merchant not to offer bargain prices. Because of this, Kenn had a very hard time earning enough credits to leave Omega and return to the Fleet, and because he was a Quarian, there was very little he could do to gain the respect he deserved as an honest salesman. Later on the Citadel, another Quarian found herself wrongfully accused by a Volus who insisted she stole his credit chit when she bumped into him. After discovering the Volus left his chit in a shop he'd visited, the Volus responded by insisting she could have taken it, while the C-Sec officer threatened to arrest her for vagrancy.
It's hard to imagine how many young Quarians on Pilgrimage don't even make it back to the Fleet, but those who do undergo the final act of their Pilgrimage: changing their name. Upon acceptance to the ship they wish to join, they drop the nar from their name, which means "child of," and adopt vas to signify themselves as a crewmember of the ship they live and serve on. As far as coming of age rituals go, the Quarian Pilgrimage may not seem as brutal as the Krogan rite of passage Grunt undertakes on Tuchanka, but taking a look at everything young Quarians must endure before returning to the fleet, one might actually say it is not only more brutal, but more dangerous.