The mitzvah of tzitzit requires fringes to be tied to the corners of any four-cornered garment worn by men and boys.
It is considered a great mitzvah to wear tzitzit throughout the day. The Torah tells us that looking at the tzitzit fringes reminds us to observe the mitzvot at all times and protects against the urges and impulses of the heart. Thus the importance of wearing tzitzit at all times is quite obvious. Nontheless, there is no requirement to observe this mitzvah unless actually wearing a four-cornered garment.
Even one who does not wear tzitzit throughout the day should wear tzitzit (or a tallit) while reciting the morning Shema and prayers.
It is customary to begin educating young boys to wear tzitzit when they reach the age of three.