In order to graduate in a timely fashion the student should have the lower division courses done in community college to the extent possible. Additionally, the student needs to sign up when advised to do so. If a student decides not to take a class depending on a work schedule or only wanting to attend on certain days of the week and not others it will likely take longer to finish coursework.
Check out the following sequences to finish in a specified time:
2 year plan (pdf file)