When does monthly usage/data reset to 0?

Is it the first of the month? or on a different cycle?

Your monthly limits get replenished on the first day of each month.

I'm seeing you already are on the Silver Plan though. In case you wanted to check and review your usage, just go to your Account's Usage section https://www.jotform.com/myaccount/usage And to have an idea what the Silver Plan allows per month, just refer back to our pricing page https://www.jotform.com/pricing

Let us know if you'll need more help :)