For some students, the choice seems easy. Maybe he grew up assuming he would attend a college that one or both his parents attended. She might have attended every home football game with her dad for a public state school.
Yet, at some point in high school, even these students may face unexpected issues with their long-standing assumptions or plan. Other schools may have programs of interest with greater funding, prestige, and/or opportunity. The planned school may not offer the major or concentration that a student has realized he or she wants to pursue. The student may decide that the planned school is too far away from -- or too close to -- home. Other schools may be indicating interest in the student's athletic or musical accomplishments. The student may conclude that grades and test scores have diminished his or her chances of admission at the planned school.
For these reasons and more, I believe it's important for every student to have a college list. In freshman year, that list could be as small as 3 or 4 schools or as large as 50 schools. During sophomore and junior year in high school, the student will explore schools via campus tours, college fairs, online research, and/or working with a counselor, and will then refine the list (adding or removing schools). By the summer before his or her senior year, the goal is to have a solid list that includes 6-10 schools. That list should include 2 safety schools, 2-4 target or match schools, and 1-2 reach schools.
Timing is important. If a student reviews her transcript and her SAT/ACT scores at the end of junior year and realizes that a planned school is out of reach, scrambling to put together a list of viable choices may not yield the best results. At that juncture, a student won't have much time to tour campuses or speak with representatives at college fairs. It also leaves the student without much opportunity to enroll in test prep or retake standardized tests. Beginning the college search process early enough to allow for relaxed pacing will alleviate much of the stress from the overall process.