EPDs (Executions Per Day)" is the total execution times of all your cron jobs each day. E.g. cron job that runs every 10 minutes occupies 144 EPDs, runs every minute occupies 1440 EPDs, etc.. EPDs will be marked as occupied once you add a cron job. If you delete a cron job, the occupied EPDs will be released back to your EPD balance. See how many cron jobs you can add in each plan.