You can run as many searches as you like, build as many lists as you like and look at as many results as you like without touching your allowance.
The count moves when Buzzlist gives you contact detail you did not have: a business email, a personal email, a mobile or a direct dial. Opening the same person again in the same month does not cost a second contact. A record with no permitted contact detail costs nothing at all.
Your allowance resets at the start of each billing month. Nothing carries over, and nothing expires while you are on the plan.
