This podcast episode discusses the optimal frequency for keyword harvesting and negating in Amazon PPC campaigns. The hosts explain that the frequency depends on campaign maturity, suggesting weekly harvesting for new campaigns, monthly for mature campaigns, and quarterly for very mature campaigns. A similar frequency is recommended for negating keywords. They emphasize that bid optimization is significantly more crucial than keyword harvesting or negating, with a suggested ratio of 20-30 bid optimizations for every one harvesting or negating session. Listeners are advised to review previous episodes (83 and 84) for context on keyword harvesting and negating criteria.