When I was a student, I figured teachers just had a syllabus and that was that -- one size fits all. Not so! With each new cycle of students, I find things I can do to my syllabus to make it more useful to both me and my students. It's also a chance for me to look at what worked, what didn't and what I can do better. Unfortunately, we don't always have time to do that; but when it's there, use it. Don;t wait until you change textbooks to rework that syllabus.
Just my thoughts ...
John