To ensure you don't miss a new email in a category, the email service provides alerts embedded within the Message List of your inbox or other folders. When new emails arrive in categories, an alert will appear, indicating the number of new emails received. For example, if you have 4 new emails in your categories, the alert will display "4 new emails in your categories. Click to view." This feature helps you stay informed about new emails and allows you to easily access them by clicking on the alert.