To keep your ads engaging, you need to update your creatives when they start feeling stale to your audience.
A good rule of thumb is to refresh them if your ad frequency exceeds 2–3 views per person, as repetition can lead to ad fatigue, but this may vary depending on your goals, audience, and platform.
For campaigns that run longer than a month, plan to update your visuals and copy every 4 - 6 weeks. Smaller audiences will need changes more frequently since they cycle through your ads faster.
If you notice a dip in click-through rates or overall engagement, take it as your cue to introduce fresh creatives to maintain interest.