This might be something that most teachers already know, but this was a life-changing realization for me!
I used to buy magnet tape like this for my classroom:
Love that it was adhesive, but as we all know, by December, the adhesiveness is wearing off. And the fact that this tape is curved means that it's pulling away from the paper I stuck it to. I am always re-hot gluing the magnet tape to things in the middle of the day. SO frustrating.
Finally I wised up and decided to order business card magnets from Amazon. They're intended to place on business cards to make them magnetic, but for me they're rectangles of flat magnet amazingness. I cut them into fourths and voila! My schedule cards, calendar, objectives posters and everything else that I need to be magnetized is done. There's no peeling away from the paper, so I don't foresee needing to hot glue or redo these in any way!
This set from Amazon is for a pack of 50.
Hope this changes someone else's life as well!