Kate's take, in a sentence or two

Kate explains that testing different sizes really means adapting creative for different placements—like reels/stories versus feed posts—rather than testing the same ad in multiple formats. She notes she's mostly stuck to square images but is now experimenting with a video ad repurposed from a webinar clip, though she hasn't personally found video to consistently outperform images. She adds that since making videos is draining for her, it's fine to skip video ads and stick with images if they get good enough results, especially when working within your capacity and energy limits.