On a reset leaderboard the entries are dropped but not the underlying running total. So if you're tracking a maximum score and score 100 on day 1. On day 2 (after the reset) you would need to score > 100 to have an entry on the leaderboard.

If you would rather start from 0 each day/week/month, you can achieve this by partitioning the leaderboard by day/week/month.