Also, sometimes ACH debits will cause unpreventable overdrafts for you. What I do now (I realize this isn't really an option for a lot of people) is basically

Also, sometimes ACH debits will cause unpreventable overdrafts for you. What I do now (I realize this isn't really an option for a lot of people) is basically mentally subtract $500 off of my checking account balance, and would never spend any money if there's less than that in there.