No. Repeated searches or verifications are counted once per billing period.
However, please note that Hunter won't detect duplicated emails or rows processed in different CSV files with Hunter's bulk features.
If you are part of a team, duplicate searches or verifications will be counted at a team level.
For example, if user A performs a Domain Search and user B (in the same team) performs the same Domain Search in the same billing period, no credits will be counted for user B.