Creative fatigue
Creative fatigue is the gradual decline in ad performance as the same audience sees the same creative repeatedly. For FE Facebook ads in 2026, creative typically loses 20 to 40 percent of its CPL efficiency around week 3 to 4 of running, requiring a refresh.
Fatigue is faster on smaller audiences (because frequency builds quickly) and slower on broad audiences. FE tends to fatigue faster than e-commerce because the FE audience is bounded by age 50-85, which is a smaller pool than general consumer ads.
Mitigation: rotate fresh creative every 2-3 weeks, vary one element at a time (different hook, different agent on camera, different setting), and use creative pools of 4-8 ads in Advantage+ so the algorithm itself rotates between them.
You can spot fatigue by watching frequency in Ads Manager (3.0+ for an ad usually means fatigue is starting) and by watching CPL drift up at a stable spend.