Are idioms a must in the classroom

Are idioms a must in the classroom or something that only native speakers have the right to use I guess those thoughts popped in your head once. So, let s cross the T s and dot the i s Some resources mentioned in the video: and my video on teaching with tweets Check out the rar folder attached to the post below, where you can find some of the common idioms and their imageries with some tasks which I ve prepared for you Happy learning teaching