It turns out that what we think is easy to learn, is also easy to forget. According to a fascinating article in Education Week, people tend to overestimate what they will remember. We especially overestimate "easy" information.
What does this mean for you as a teacher?
For me the article reinforced how important it is to go over routines, review concepts throughout the year, and take the time to really teach easy, but important ideas. The article said that when people review easy information 5 times, they are much more likely to remember the information later.
One way I review concepts and ideas we learn in the classroom is my weekly Friday game. For the game, I put the class into small groups and ask questions that cover everything we have learned over the course of the year. Any flashcard that we have created, anytime over the year, is fair game. This way, ideas and concepts get reviewed multiple times. The students love the game, which we play like Jeopardy, and it is a rewarding, fun way to build review into our week.