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Ad Platform Playbook

Bid Strategy Selection

Conversion volume thresholds, platform-specific nuances, and when not to change strategy

For · Operators choosing or revisiting a bid strategy
Time · 6 min read
Next · Campaign structure principles

Conversion volume is the single biggest factor in choosing a bid strategy. Automated strategies need conversion data to optimize; without enough signal, they can underperform manual bidding.

The Short Version

  • Conversion volume decides the bid strategy. Below roughly 15 conversions per campaign per month, automated bidding has too little signal to beat manual.
  • The thresholds apply at the campaign level, not the account level. An account at 80 conversions can still hold a campaign at 8 that should not be automated.
  • Microsoft is explicit where Google is not: below 30 conversions in any 30-day period, Maximize Conversions stops optimizing bids.
  • Enhanced CPC has no documented minimum, which makes it the practical middle ground for a campaign that is not ready for a fully automated strategy.
  • Do not change strategy on the heels of another change. Negative keyword additions, keyword pauses, and structural edits all need time to settle first.

Conversion Volume Thresholds

Monthly Conversions (per campaign)Strategy Options
Fewer than 15Manual CPC or Maximize Clicks
15-30Maximize Conversions (borderline for Target CPA)
30-50Target CPA can be viable
More than 50Target CPA or Target ROAS

These thresholds apply at the campaign level, not the account level. A campaign generating 8 conversions per month may not benefit from automated bidding even if the account as a whole generates 80.

Platform Differences

Google Ads doesn’t publish a hard conversion minimum for its automated strategies, but performance typically degrades below 15-30 conversions per month per campaign. Google’s own documentation maps strategies to goals without addressing volume thresholds directly.

Microsoft Ads is more explicit: if a campaign falls below 30 conversions over any 30-day period, Maximize Conversions stops optimizing bids. Enhanced CPC has no documented minimum, making it a practical option for lower-volume campaigns.

Enhanced CPC vs. Manual CPC vs. Fully Automated

  • Manual CPC gives you full control over keyword-level bids. It works at any volume but requires active management.
  • Enhanced CPC adjusts your manual bids at auction time using device, location, and time-of-day signals. No minimum conversion threshold. A reasonable middle ground when volume is too low for fully automated strategies.
  • Maximize Conversions / Target CPA / Target ROAS use historical conversion data to set bids automatically. They can outperform manual bidding when conversion volume is sufficient, and underperform when it isn’t.

When Not to Change Your Bid Strategy

Timing matters. Changing your bid strategy right after other campaign modifications can muddy the data and make it harder to understand what’s working. Consider holding off if you’ve recently:

  • Added negative keywords (give the traffic mix time to settle)
  • Paused keywords (the remaining keywords may shift performance)
  • Seen a drop in conversion volume (less data means the new strategy has less to work with)
  • Made other structural changes (isolate one variable at a time)

Trellis Perspective

Trellis audits evaluate bid strategy fitness at the campaign level, not the account level. A recommendation to change strategy for one campaign doesn’t imply the same change for another, even in the same account. Confidence in the recommendation scales with the conversion volume available for that specific campaign.

Sources