Your trial period is extended everytime you press publish, so you can keep your trial going as long as it takes for your site to be ready to go live.
Each time you press publish, your trial site is automatically extended for another 30 days. The 30 day trial limit is in place for those that start a trial who do not decide to continue building a site using the CMS - it's a way for the system to clean out unused sites.
If you do not press PUBLISH and let the site sit untouched, the system will send a notification email out to the address specified when signing up informing your site is in danger of being deleted. You can either get in touch with us to extend the site, or log in to the site and re publish.
If you decide to do nothing, and the period passes the expiration date, after an amount of time the trial site will be deleted and all the content will be lost.