Do I get a notification if I am getting close to the submission limit?

I am thinking I will eventually upgrade to a premium account, but want to try it out on something small first to see if it works for us. Just wondering if there is some kind of warning that I get if I am getting close to the limit so I can upgrade if need be. I just want to make sure that customers will be able to register for my event smoothly. Thank you!

You will receive an email if you reach the subscriptions limit:

This email will also contain a link to upgrade. 

In addition you can set up limits for submission of you form, after which the form becomes unavailable:

Let us know if we can assist you further.