A workable cadence is daily spend pacing and anomaly checks, a weekly optimisation pass with a short written note covering what changed and what you should expect from it, a monthly live review against acquisition-cost and payback targets with an explicit decision list, and a quarterly channel-mix re-plan. Monthly-only reporting is too slow to catch a broken campaign in a market where budgets move fast.
What gets reported matters more than how often. Impressions, reach and engagement answer a question you did not ask. Cost per qualified lead, customer acquisition cost and payback answer the one you did — and all three should be measured against a written baseline captured before the agency changed anything.