We often put too much attention on creating an ad that will be remembered. That it will be so different, so edgy, so original, that people will have no choice but by clicking on it.
If you are -or have someone in your team- with that creative power, you will see the results reflected right away: relevance score high, more clicks, shares, and conversions.
Eventually, people will stop clicking on the ad. They know what it is about already, what they would get, they will take it for granted.
Ad fatigue is something real. But, how real is it if people only saw your ad twice? If you look at your frequency metric, and among all the people you are targeting, they saw your ad on average 2 times, how can they be bored about it?
If you are refreshing your ads to prevent ad fatigue, make sure to do it at the right time: you’ve reached all the people in your audience, and they’ve seen your ad at least ten times (or maybe 20 times?)