In my classes, I had an unspoken policy that each student received eight classes. It didn't have to be consecutive weeks. Meaning, if a student should up once a month, that student would receive 8 weeks of educating spread out over 8 months.
However, I am now lining up my policies with that of the school I teach at. Meaning each student receives eight consecutive classes from the time he or she starts. If a student misses one class and calls 24hrs ahead of time to notify the instructor, he or she is entitled to one make up class, but any more absences will result in a forfeiture of that week's training. Not calling ahead of time results in a forfeiture of that week's training as well.
No long will students be able to spread out their education over 8 months.
And here is why: people in general and students especially need to practice regularly to retain old information and prepare their mind for new information. Practicing irregularly and sporadically results in forgetting old concepts and having to relearn them, making it impossible to teach new information.
You cannot imagine the frustration I feel re-explaining the same concepts to the same person because the student simply doesn't practice.
If you plan on sporadically dropping in, it is best to save your money and choose the single class option. Signing up for 8 weeks means 8 weeks in a row from now on.