They're not taking a full course load. This may be the biggest financial sinkhole (I mean secret) of all. Graduation rates vary depending upon the school, but in general, it's taking kids longer and longer to finish their degrees -- as many as six years, in some cases. At many schools, taking just three courses per semester is considered taking classes "full time," and as a result, will cost you full-time tuition -- the same amount you would pay for four or five courses per semester (which is what most students need to take to finish in four years). Make sure your child knows that the three-course minimum is unacceptable, and that you won't be paying tuition for a fifth year of school.