This depends on how many feeds you follow, and which delivery options you selected for every feed.

For example, if you selected the “Newspaper” delivery option, you’ll receive one email per day with the stories that have been published in the last 24 hours.

The Newspaper avoids information overload. However, if you want to get informed faster, you can select the "Single Email" delivery option which sends out an email as soon as we found a new story in the publisher’s feed. Also most other delivery channels update you soon after the stories’ publication.