That's a Fantastic Question that Needs Some Explanation
This is an interesting question. The answer is yes and no.
Here's a short video walking through this question:
Campaigns have a timeline: For example, you may have a landing page that gets published immediately, ten emails that go out over 10 weeks, and social media posts that go out over a month.
Once social media posts finish their course, they do not start over.
However, emails work differently.
Emails work in relation to the WHEN someone has been added as a subscriber.
Example: You launch a campaign today and add 50 people to it as subscribers. They will start receiving their emails according to the timeline shown in the campaign.
However, if those 50 people are now on week 5 of their emails, and you happen to add a new group of people, those new people will start their journey with your campaign from the very first email in the series.
If you ever want to add new people to a campaign, you don't have to start a campaign all over again. This saves you time.
You can subscribe them to a campaign, and they will begin receiving their emails as intended.