We plan one year in advance and have kept the same schedule for many classes for a long time (CPR, ACLS, PALS, etc). That way we know when we will have the peaks. When we have low census more people can come to class, but that is exactly when we are not allowed to have classes due to cost. To keep costs really low we use contract outside instructors (usually firefighters) to teach CPR, etc. as they are cheaper than our own hourly staff.