Say you found a winning banner, but it's not quite there, maybe like at 10% ROI or something.
With how quickly banners burn out, do you think it's even worth testing sub-headlines?
I'm just trying to find the last places I can squeeze ROI out of lol
For me most of the time it's all about image.
However I tend to run in big geos, so it takes really long to burn out the banner (= CTR going down).
Most of the time when it "burns out" (CTR down) it's just a signal that someone did overbid me.
Make sure your funnel aligns together.
So the banner image and angle matches good with your landing page angle and all that with the offers itself.
You need to maintain this magical balance 
I don't remember exactly where I read this but CTR breakdown is 70% image 20-30% headline 0-10% else
How fast are you experiencing banner burn out?
Thanks for the responses guys.
Im also running in large geos, so I'm just trying to squeeze out every last bit of ROI I can since the ROI in these geos tend to be lower.
So I was just curious if you guys do split tests with these.
For sure man all good!
Any boost in ROI you can get is good but I feel like it will come more so from testing more images/angles or finding competitive advantage with offers/relationships then testing minor adcopy variations