There are several things you can do to control student access, keep your course lists manageable, and maintain some records.

Student access

Students who are not registered for classes the next quarter will be able to access Canvas for two weeks after grades are due. Then their access cuts off until they register again in the future.

For students who are registered for classes the next quarter, it depends on the dates the instructor sets in the course settings. Students are not removed from courses, nor is there a specific date when courses are closed. There are two options for managing what students can see after the quarter is over.

When you choose, consider the benefit students may get from future access to the course. Continued access to your course can help students:

If they are participating in the next course in a sequence. The ability to refer back to previous material may be valuable.
If you have linked to many of the reading materials, the Canvas course may be the best way for them to find those references. (How many notebooks and textbooks did you keep after you finished a quarter of school?)

The two options available are:

Completely hide access: This option means students no longer have access to any of the course materials. To do this, set a Start and End date in the course settings, and click the box labeled "Users can only participate in the course between these dates."

Selectively hide access: Assignments, Discussions, and Quizzes can be set to disappear at a certain date, and you can do that when you are first creating them. If you haven't scheduled that, you can go back and hide any items you don't want freely available (e.g. exam answer keys) at the end of the quarter.

Allow access: This approach allows students to access the materials as long as they are enrolled at or employed by Highline. As long as you have not added an End Date in the course settings, students will be able to access the materials.

Managing your course list

Canvas shows a list of your "favorite" courses in the Courses menu. As you teach more classes, this list can become overwhelming. You can limit the contents of this list by customizing the course menu.

Canvas Guide: How do I customize my Course list?.

Archiving grades and courses

While Canvas doesn't move content off-line, you may need copies of records for future courses (e.g. for accreditation purposes). Two actions you might want to do:

Export a copy of your gradebook, Canvas Guide: How do I export grades in the new Gradebook?
Export the course, Canvas Guide: How do I export a Canvas course?