Rising frequency with falling click-through rates is often the first signal, showing people are seeing ads but engaging less. Monitoring metrics like diminishing conversions, higher cost per acquisition, and lower engagement on repeated exposures helps confirm the pattern. Session data and funnels act like logs, revealing where users stop responding or start skipping ads. Comparing creative performance over time highlights which ads wear out fastest. Comments or feedback signals can also reveal annoyance or irrelevance. Together, these patterns show when repetition starts hurting results instead of helping.