Premium Site Lead Duplication Cycle

Do we have a de-dupe cycle? (If a lead comes to our site, downloads the Buyer's Guide, and then does it again six months later, is that considered a new lead?) 

What is the time frame for this type of duplication?

Leads have two parts:

A) Accepting Leads: 

We reject any lead from the same user with the same lead_type and data (e.g., category lead, category ID) on the same day.

B) Delivering Leads:

We will not deliver the same user/lead within 6 months to more than one campaign of a vendor.