SPOTTING CTR DECAY EARLY: HOW TO CATCH AD CREATIVE FATIGUE

Summary from the TLDR Marketing newsletter

Creative fatigue shows up as one ad's CTR sliding week after week below its own launch-week level while frequency climbs and the other ads in the same ad set hold steady. A single early drop that then flattens is normal settling, not fatigue. CPM rising on every ad at once points to the auction or the calendar instead, and frequency rising while reach plateaus points to an exhausted audience. Meta's own “Creative fatigue” status only appears once cost per result doubles, well after spend is lost.