Rather than requiring a predetermined amount of time as public secondary education programs do, colleges confer a degree upon students only after they complete a designated number of course credit hours. Requirements may vary slightly between educational institutions, but most colleges award an associate's degree after 60 semester hours or 90 quarter hours of study. These hours, of course, must be spent in a designated course of study; simply achieving the requisite number of credit hours is not sufficient to earn a degree.
Some students view college as simply a learning experience and prefer to take a hefty number of electives (or optional classes) while working toward a degree. While a certain number of electives is required to earn any type of degree, taking too many electives can derail a student's educational endeavor and draw out the educational experience. When a student first enrolls in college, the school provides a recommended course of study; a certain number of electives are already included in this "road map" and, while expanding a student's horizons is encouraged, taking more than the required number of electives almost certainly extends the time needed to earn the degree.
The learn-as-you-go nature of college allows a tremendous amount of flexibility for working students, students with children, and other personal circumstances. Traditional estimates of how long it takes to earn an associate's degree assume, though, that students enroll in full-time course loads (the "full time" designation varies from school to school, but most schools consider students with 12-18 credit hours per semester to be full-time students). In general, students who maintain full-time enrollment and strictly follow the recommended course of studies can earn an associate's degree in approximately two years, though this time frame is extended somewhat if the student takes fewer classes, does not earn a passing grade in any course, or becomes derailed with excessive elective work.