What is Spiral Review?
Spiral review, or spiraled practice, is a method of giving your students repeated opportunity to practice skills they've already been taught to help them keep their skills fresh.
Students may not grasp a concept the first time around, but by having multiple experiences with the concept throughout the year, they will surely have time to understand it by the end of the school year.
Research supports the use of spiral review. In fact, this method (sometimes referred to as distributed practice), has such a strong research-base of support that it is recommended by the Institute of Educational Sciences (IES).