I'm not talking about sending your toddler out on his own. I'm talking about giving your children increasing responsibility, followed by age-appropriate privileges.
Children who are overly sheltered face a rude awakening when they venture out on their own - and rest assured, they will some day venture out on their own, whether they are prepared or not. As parents, it is difficult to see our children hurt, disappointed or limited. With the exception of harmful situations, let them experience these feelings for themselves. They will discover their strengths and develop the coping mechanisms they will need when you are not there to shelter them from life.
Remember that challenges are opportunities to learn, grow and become stronger. Isn't this what you want for your children?