Hi Kristin,
Thanks for checking out Events Calendar Pro!
Buying the license (which is good for one year) entitles you to plugin updates and premium support during that time. Once the license expires, you will no longer be able to update or post in the support forums, but the plugin itself will not be affected. Over time, you may run into compatibility issues if you do not update (as WordPress and your theme/other plugins are updated), but otherwise your plugin and existing recurring events will continue to function just as they did before the license expired.
We do offer full refunds within 30 days of purchase, so if you’d like to take Pro for a test run, feel free to do so! Please let me know if you have any other questions.
Thanks,
Jennifer