Has anyone used the ARRL material to study for one of the licenses? I was looking at this Studying for a Technician License to study for the technician license, but notice this edition is good through 06/30/22. I would think the material would be good to study and still pass the test after that date as long as you have an idea of the principles and methods of how to figure out the answers? Should a person wait till July to get the latest edition and study?