I cannot emphasize enough on Structure and Routine in a child's life. Structure is about having a planned day, divided into meal times, study times, structured play times, unstructured leisure and sleep times. Routine is all about doing these things at a specific time, in a specific way.
Let me explain further. Infants, toddlers, young children and adolescents have a very high need for exploration fueled by their natural curiosity. This tendency allows them to learn new things through experience and master some age appropriate skills (playing peek-a-boo teaches a toddler about object permanence, searching for toys teaches the preschooler figure ground perception, learning numbers at school allows him to count his toys, taking part in sports teaches a teenager team spirit etc). But like any exploratory activity, it has risks of the unknown (will my mom who is hiding behind the chair come back? or will I ever find my favourite toy in the toy chest? or will my classmates laugh at me if I don't say the numbers in the right order, will I become a laughing stock with the girls if I don't score a single goal). It may seem like an insignificant thing to an adult but it causes unconscious anxiety and fear in the kids. The automatic response to anxiety (or any stress) is to seek to decrease it.
Feeling safe and protected brings down the anxiety. As parents we provide that through hugs, reassurance and love but it also makes them dependant on us. And, we may not be around all the time. Mom and Dad have to go to work, the kid needs to go to day care or school where the teacher may not have the time to attend to every child. The resultant anxiety could manifest into clinging behavior, frequent crying or temper tantrums, defiant behavior, truancy, experimentation with addictive substances etc.
The only way to decrease this anxiety and help the child cope with the daily struggles of navigating the complex world is by providing the safety net of sameness of routine and structure. Knowing that Mom will pick me up from school after lunch, Dad will read me a story at bedtime, we will have a meal together every night or that I will go for swim lessons every weekend after breakfast can be very reassuring to a child.
Predictability is encouraging and adds to the reserve strength to deal with the other unpredictable inevitabilities of life.
Sameness breeds security, develops confidence to explore new things and take risks. The presence of routine and structure is like a launch pad for the child to learn new things, understand his strengths and explore his potential. Does it then mean that if we have structure and routine in our lives, we will raise confident and successful kids? No. But we will certainly raise kids who are confident enough to try new things, who seek resolution of their stress in adaptive routines and who will focus on reaching their potential.