Developmental milestones are a set of functional skills or age-specific tasks that most children can do at a certain age range. Every child has an average time frame for physical, social, mental and emotional development. The first five years of a child's life are the most important for a child's development. Skills such as crawling, standing, taking a first step, keeping balance, reading, smiling for the first time, eating, drawing and waving are considered to be important developmental milestones. Children reach milestones in how they play, learn, speak, act, and move (crawling, walking, etc.). Although each milestone has an age level, the actual age when a normally developing child reaches that milestone can vary quite a bit so children may achieve developmental milestones sooner or later than the average and reaching these milestones later than expected does not necessarily indicate cause for concern; many infants develop at their own pace but parents breathe a sigh of relief when their child achieves a milestone at the right time. In case there is a delay, parents experience a great level of anxiety about it.