Depends on the class I'm giving what I bring out, but I got tired of dragging boxes and bags of things to the classroom at the gun club and now just have students come to my house. Then I can get out anything we need. I limit classes to just five students each, so it's not a problem.
For a basic pistol class, I have all of the materials listed in the NRA teacher's manual, as well as supplemental material I've developed over the years. The box of holsters comes out for the CC class. The one that involves the most materials is the "Personal Protection in the Home" class. Lots of stuff to simulate a "safe room," cover and concealment, and much more.
If you only give a class once a year, I do hope you are reviewing your teaching aids carefully, starting several days in advance. Best advice is to keep it as simple as possible. It is easy to wind up with too much stuff... I go through my tote boxes before each class the night before and set out only what I think I will actually need. The rest is there if I find I have to get it out, but most of the time the presentation of the basics is best kept simple.