Duplicate checks alternate a carbonless check with a plain piece of paper. When the user writes on the original check, an exact duplicate is made on the plain paper underneath the check. This paper copy aids in record keeping and eliminates the need to maintain a checkbook register. Single checks do not have this feature, as the checkbook consists only of checks. The user is responsible for writing down the payee and the amount in a checkbook register for record keeping.
Number of Checks
Checks are sold by the box, and the number of checks within the box depends on the company printing the checks. Regardless of the company, there are always fewer duplicate checks in a box than single checks. This is because duplicate checkbooks are thicker than single checkbooks and fewer checks can fit into the box.
Duplicate checks are consistently more expensive than single checks. Not only do you get fewer checks per box, you also pay more money for that box.