@CathyHardy-Parc I believe the design is more for caring about when it goes out to students instead of how long they can see it. An announcement is a notification, such as "reminder, quiz tomorrow, bring your calculators" and so it is really only important about when it goes out (again, in the design). Students will get notified of the announcement (assuming they have not turned off notifications) so once it is out, it is out.
I am guessing you are not wanting to have it available after a certain date as it may no longer be relevant...??? That would make a good feature request at least for people that have their announcements show on the homepage. For people that use a purely a notification, they probably would never use it as once the students have been notified, they already know so there is no pulling it back. You can manually delete the announcement which removed it but I realize that is an extra step.
Hope that helps!
Thank you for your reply. However it does not solve the issue. In a previously used LMS an announcement could be set for a beginning time/ date and an ending time/ date. On Sundays at 12:00AM it would be available and on the following Saturday at 11:59PM not would be not available. 1 minute later the next weekly announcement would come on. An instructor could decide to use that feature or not. The choice was theirs. Canvas should have a feature that allows an instructor to set beginning and ending times/ dates if they choose. One should not have to manually publish or unpublish items. All items in Canvas -announcements, modules, quizzes, exams, etc. should have that feature. Thank you.