A number of adjunct professors (and professors who are not adjuncts as well) simply reuse old syllabi for new classes. They simply find one that was for the same course and met the same number of days per week. Having taught a course one day a week, the same course two days a week and the same course three days a week, it is really easy for me to do this.
I confess that I always go back to an old syllabus as a starting point. For instance, this semester I will be teaching a course that meets two days a week and one that meets three days a week. As a STARTING POINT, I will go back to an old two day a week course, update the days and dates, and I have a new syllabus. I will do the same for the three day a week course.
It is important though that this only be used as a starting point. While I have been teaching as an adjunct for a number of years, I am always encountering new and different situations. Sometimes these situations are due to student issues I haven't encountered yet. Other times, they are do to what is happening in my life. Also, they can occur due to advances in technology. I always try to update my syllabus each semester, to address the new problems I have encountered. I like a detailed syllabus. It helps to ensure the students knew just what you expect. Even if they don't read it, I know that I have fulfilled my end of the contract and I can show it to them in black and white.
I beleive this has helped make me a better instructor and allowed the students to have a more positive experience in my class.
Teaching as an adjunct can be a lot of fun. It is also challenging. As I have encountered a number of situations, I realize such a blog can be helpful, both to me and to others.