Don't throw your older leads away. Sometimes it's your older leads that will become your most trusted and longtime clients. Just because you have not spoken with them does not mean they are still not wanting to purchase a property. You have the opportunity to build that relationship with them and attain the sale.
Why your oldest leads can offer the biggest rewards
Resurrecting old leads - The Power of Mass Texting
Speaking with older leads vs. new ones is there a difference?