This is a fair question and there are many definitions of a lead. I prefer to break them down to types.
Someone that is moving now or in the future, OR someone we can put into a marketing enhanced prospecting system to generate referrals from.
Let's start with someone that is moving group first. This is someone that can answer why, when and where. It is my belief that if they do not answer those three questions, they do not qualify to be in this category.
Once we have established that someone is moving and you know why, when, and where. Then they fall into two categories, inside 30 or outside 30. This simply means someone that is going to do something inside of 30 days or outside of 30 days, which could be list or purchase a home. (Remember when someone tells you they are going to do something in 2 months you can safely cut that in half)