It opens doors of independence and privilege that you will only be aware of as your child ages and remains in diapers. Not being toilet trained limits your child's options for child care, school programs, and, if it goes on too long, may be one of the factors that leads to more-restrictive placements at school or residential programs in the future. Make sure you have set aside a lot of time to devote to toilet training, especially in the beginning. Azrin and Foxx recommend taking a day off from work to devote to a full day of nothing but toilet training. For us, let's start with a week off from work.
Many parents opt to have the toilet training begin at pre-school or school.
That's okay but make sure you are aware of the methods they are using and do the same at home. Choose a method and stick with it. They say a habit takes three weeks to become a habit. Give any method at least this long to see if it works. See the Internet links below for the methods.