From Mark DeVries’ Family-Based Youth Ministry, Rev. Ed., p. 87 (emphasis added):

“When a student makes it to mature Christian adulthood, he or she can almost always point to either the influence of godly parents or that of at least one available, durable, nonexploitive Christian adult who modeled for them what being an adult Christian was all about. Sometimes twenty-something youth directors can make this kind of long-term, ongoing investment in a handful of students, but by and large, their age-driven transience severely limits their long-term availability.”

Youth ministers: try to put down roots and invest in the lives of a congregation’s kids for a number of years. If you have to go sooner, keep yourself available to those students with whom you have forged relationships.
This is important stuff we do; it’s not to be entered (or exited) lightly.