There are several ways to turn on email notifications so that you are notified when someone posts or replies in the community.
When you create a new discussion or reply to someone else's you are automatically subscribed to that discussion. That means that you don't need to check back to see if anything has happened. You will get an email as soon as there's activity.
Here's a quick video that shows you the various places that you can control your email notifications. For example, following a specific topic.
(We did this video for Portable PA but the methods are applicable here too.)
Here is another video that shows how you can get notifications for all activity in the community.
Control your notifications and enjoy your community.