If you’re testing just a new creative (like your new video), and everything else stays the same (audience, placements, bidding strategy), then you can simply add it as a new ad within the existing ad set.
Here’s why that makes sense in your case:
Your budget is set at the ad set level, so Meta will automatically start allocating spend between the old and new ads based on performance.
Since you’re targeting the same audience, there’s no need to duplicate the ad set unless you want to test the creative in isolation.
When to use a new ad:
You're testing a new creative (video, image, copy) and want to compare performance under the same conditions.
You want Meta to optimize between multiple creatives automatically.
When to use a new ad set:
You want to control budget between creatives.
You're testing a new audience, placement, or optimization goal.
You want to avoid creative overlap or keep performance cleanly separated.
So in your case, just create a new ad inside the same ad set. If you find later that the new video needs its own dedicated spend, then you can duplicate the ad set and isolate it.
