Weekly — pacing review: spend vs. plan, CPL by channel/campaign, creative-level leading metrics. Decisions: pause losers, scale winners (your nobi- / fla7- type sets), shift budget off low-intent placements.
Monthly — cohort review: true cost-per-activated-customer by channel for cohorts old enough to have cleared ETA. Decisions: budget reallocation, blended CAC vs. LTV, payback period.
Quarterly — channel-mix and the organic-vs-paid gap you already flagged (e.g. the invoice-downloader demand with no paid support).