Many communities are now offering preschool as part of their public education. Some offer preschool to those that are low income or those whose have a child that is developmentally delayed. In these cases, there is no cost to the parents.
But this is the exception and not the rule. So, each family will have to look at the cost of sending their child and see if it fits into their budget for one or two years. Is there a parent at home that can qualify to teach the preschooler at home? Some parents have degrees in early childhood education while others have taught themselves. If this is not the case in your home, you may want to send your child to someone who is better qualified. You may head to http://www.lemanmanhattan.org/ to know more about primry schools.
When entering kindergarten, there are expectations that your child will have some basic academics under their belt. Kindergarten used to be the place to begin learning numbers and letters but in most school districts this is not the case. Your child will be expected to have these basic ideas begun but not necessarily mastered as they enter kindergarten. Preschool can give them this foundation.
Another consideration when determining the need for preschool is the personality of the child. If your child is with-drawn, shy or uneasy around other children, it would be essential to expose them to preschool so that they will interact with other children.