4 out of 10 kids who start a four year degree don't finish in 6 years.

[ucbalumnus]

https://catalog.ufl.edu/ugrad/current/regulations/info/graduation.aspx#summer

@University of Florida

Students who enter a state university in Florida with fewer than 60 credits must earn at least nine credits before graduation during summer terms at State University System (SUS) institutions. However, students who earn six credits through UF-sponsored, UF exchange or approved SUS study-abroad programs during one or two summer terms completely satisfy the summer-term enrollment requirement. In addition, credits earned through any of the study-abroad programs approved by UF during a summer term count toward satisfaction of the summer-term enrollment requirement. Students who bring 60 or more transfer credits to UF, regardless of institution, will be exempt from completing the summer requirement at UF.

Basically, you need the 9 credits of summer session courses (6 if from study abroad in the summer) unless you came in with 60 or more credits. Entering frosh with substantial numbers of credits could theoretically use those credits plus the required summer session to take fewer than 8 regular semesters, if their majors’ prerequisite sequencing does not prevent that. But how common is that?