Because the mid-sole material of an athletic shoe takes a pounding and eventually loses its ability to provide your child's foot with adequate support or cushioning, experts, such as Dr. Michael Lowe, past President of the American Academy of Podiatric Sports Medicine, and long time team podiatrist of the NBA's Utah Jazz, recommend periodic replacement of athletic shoes, even if the bottom sole shows no sign of excessive wear.
To get started in track & field, all one needs is a decent pair of running shoes which can be purchased either at a chain store that sells athletic equipment, or a specialty running store. At track meets and practices with a youth track club, most of the kids will also have a pair of spikes, which, depending on the age level, may or may not be specifically made for that event.