Is this an open class to all members as a drop in? Or is it a pre-register class that has a separate fee? If it is a class offered to everyone who has a membership, then the class should be held regardless of attendance. If it is a separate class paid for only by those taking the class, then you should have a preset date by which a minimum number of people must enroll and pay for the class for it to be held for the session. You can’t grow a member drop in class without some small classes. If people can’t count on the class being held, they won’t show up. I would let the class run for a month or two. If you can’t get more people signed up, take the class off the schedule. I would try to get member feedback on the best time to offer the class. Not knowing more about your facility and how many classes you can offer at any given time.