It’s simple: Pay 2x credits of your maximum list size for 1 month and everyday validations.
Let’s assume you have a list containing 100 emails. You estimate the recipients will grow to 150 in one month. While setting up a list monitoring, you select your max list size of 150. It means you predict the subscribers will reach this number and our monitoring engine allows your list to have max. 150 emails on it. If the recipients exceed this number, the monitor will pause.
You pay 2x credits for one-month validations. In this example, you will pay 150*2=300 credits for one month and everyday validations. The list monitoring engine checks all emails in your list every day for 30 days (or the time frame you have selected).
If the platform finds any problem with your billing, connection with your ESP, or anything else, it will notify you by sending an email. So, have an eye on your inbox if you have a running list-monitoring task.