Preschoolers are still learning about boundaries. They are a physical bunch who need to learn in school about working in groups and maintaining personal boundaries. Some rules that address these limits include instructing students to offer adults a high five instead of a hug, using a rug with spots on it for each student to sit on without touching anyone else and a strict no-hitting rule. These rules help students learn how to interact physically in an appropriate way.
Some rules set limits that are required for personal safety. These might include no running, the safe way to carry pencils and scissors, and no climbing on furniture or equipment in an inappropriate way. In many situations, preschoolers are too young to think far enough ahead about whether their actions are safe for themselves and others. Setting rules and limits for purposes of personal safety help them learn these skills.
Indoor and outdoor time at school require different sets of limit-setting rules. Students should be taught to speak quietly indoors, to sit in the appropriate spot during lesson time and to follow teacher directions for doing their work and cleaning up afterward.
Outdoors has a different set of rules. Students may be allowed to use outdoor voices on the playground and play with more freedom, but there still needs to be rules about running and climbing, putting toys away and playing nicely with one another.
Preschool students are old enough to make some choices, but are too small to be given unlimited choice. For the best results, give students two choices at a time. Rather than offering them all the toys in the room to play with, give them the choice of two, for instance. Or offer your class two books to choose from during reading time. This rule is more for you than them, but it will help reduce headaches that come with very young children who can't make up their mind or make inappropriate choices.