By default, user’s last 6 passwords are remembered, maximum is 24.
The Enforce password history policy setting determines the number of unique new passwords that must be associated with a user account before an old password can be reused.
The possible values for this Group Policy setting are:
The Group Policy architecture is flexible and allows for many types of design. The guiding principle as you design your organizational unit structure should be to create a structure that is easy to manage and troubleshoot.
Delegation of authority, separation of administrative duties, central versus distributed administration, and design flexibility are important factors you'll need to consider when designing Group Policy and selecting which scenarios to use for your organization.