What is the purpose of post dated checks?

Most people believe that banks cannot honor a check prior to the date written on a check. (These people are, to put it simply, wrong. Under US law, a bank may honor a post-dated check unless the account holder has specifically put them on notice of that particular check, generally by a procedure similar to that required for putting a stop payment on a check.)

The reason people post-date checks, then, is to keep them from being honored prior to a particular date.

You should HIGH LIGHT THE DATE! This is to make people LOOK at the date! In today's time, the world has forgotten the basics, do NOT count on that check being held until that date.