When should I switch from Manual CPC to Maximize Conversions?

When the campaign has at least 30 conversions in the trailing 30 days, ideally 50. Below that threshold, the algorithm has insufficient signal to optimize against and Manual CPC produces more predictable results. Switching too early is the most common bid-strategy mistake. The algorithm needs data; under-fed it produces erratic spend without conversion improvement.

Is Target ROAS the right strategy for ecommerce?

Only when the conversion value tracking is reliable and the account has enough conversion volume (50+ in 30 days, ideally 100+). Target ROAS without accurate conversion values produces phantom optimization. Many Shopify accounts run Target ROAS against the Shopify default purchase event with no margin or product-level value adjustment, which is the worst combination: the algorithm optimizes for revenue that has no relationship to profit.

What is the most common bid-strategy mistake I will find in my account?

Maximize Conversions on a campaign that has not produced enough conversions to justify it. The algorithm spends aggressively trying to find the conversion pattern, the spend goes to expensive auctions where the conversion rate is poor, and CAC degrades over the first 30 days without obvious cause. Manual CPC with a tight CPC ceiling fixes this in most cases until the conversion volume warrants a switch.

Should I run different bid strategies on different campaigns in the same account?

Yes. Bid strategy is per-campaign, not per-account. Brand search campaigns usually run on Manual CPC or Target Impression Share (defending the brand auction). Cold acquisition campaigns run on Maximize Conversions or Target ROAS depending on conversion volume. Retargeting campaigns often run on Target CPA. Mixed-strategy accounts are normal and correct.

How long should I wait before changing a bid strategy?

After any bid-strategy change, give the algorithm at least 14 days before evaluating the result. The first week is the algorithm's relearning phase and the spend is volatile. Pulling the strategy back inside 14 days because performance dipped on day 5 is the second most common mistake operators make with bid strategies. Hold the change long enough to read it.

The 20-Minute Google Ads Bid-Strategy Audit

Why bid strategy is the highest-leverage check

Bid strategy decisions are made once during campaign setup and then almost never revisited. The original choice was usually right for the stage of the account at setup. The account scales, conversion volume changes, the right strategy shifts, and the bid strategy stays the same. Most accounts have at least one campaign running on a strategy that no longer fits.

The reason this matters is that bid strategy controls the auction behavior. Manual CPC respects your ceiling. Maximize Conversions ignores your ceiling and spends whatever the algorithm thinks will produce a conversion. Target ROAS spends against a value model that the algorithm may or may not have enough data to trust. The wrong strategy on an under-fed campaign spends aggressively into expensive auctions where the conversion rate is poor; CAC degrades within the first 30 days and the cause is usually invisible from the surface metrics.

The 20-minute audit tells you whether each campaign is on the right strategy for its current stage. It does not tell you what the perfect strategy is. It tells you which strategies are clearly wrong and what to switch them to.

The audit, step by step

Open Google Ads. Go to Campaigns view. Filter for active campaigns only. For each campaign, do the following.

Step 1. Read the bid strategy column

Add the Bid Strategy column to your campaign view if it is not already there (Columns → Modify columns → Attributes → Bid strategy type). The strategy will be one of: Manual CPC, Enhanced CPC, Maximize Clicks, Maximize Conversions, Target CPA, Target ROAS, Target Impression Share, or Maximize Conversion Value.

Note the strategy for each campaign. Then move to step 2 and check the conversion volume.

Step 2. Check trailing 30-day conversions per campaign

Set the date range to "Last 30 days." Look at the Conversions column for each campaign. The threshold rule is straightforward.

Manual CPC or Enhanced CPC: works at any conversion volume. The algorithm is not making bidding decisions, you are. Volume is irrelevant.
Maximize Conversions: needs at least 30 conversions in the trailing 30 days. Ideally 50. Below 30, the algorithm has insufficient signal and spends erratically.
Target CPA: needs at least 30 conversions. Same logic as Maximize Conversions; the algorithm needs to learn the conversion pattern before optimizing against your CPA target.
Target ROAS: needs at least 50 conversions, ideally 100+. The algorithm is not just learning the conversion pattern, it is also learning the value distribution. More data needed.
Maximize Conversion Value: same as Target ROAS. 50+ conversions, ideally 100+.

Mark every campaign where the bid strategy needs more conversion volume than the campaign has been producing. Those are your candidates for change.

Step 3. Check whether conversion values are real

If any campaign is on Target ROAS or Maximize Conversion Value, ask one more question: are the conversion values you are passing to Google reliable?

Open Tools → Conversions. Look at each conversion action that the campaign optimizes against. Check the value column. If the value is "Use the same value for each conversion" set to a flat amount that does not reflect actual purchase value, the algorithm is optimizing against a fiction.

The Shopify default purchase event passes the order total. That is acceptable for revenue ROAS targeting if your gross margin is consistent across products. If your margin varies materially by product (it almost always does), the Target ROAS optimization is rewarding the algorithm for chasing high-revenue low-margin orders. The fix is to pass margin-adjusted value, not order total. That is its own setup project; the audit just tells you whether you are running on real values or guesses.

Step 4. Check the Recommendation tab for forced changes

Google Ads frequently recommends switching campaigns to Maximize Conversions or Target ROAS. Some of these recommendations get auto-applied if you have auto-apply enabled. Check Tools → Recommendations and the auto-apply settings on each campaign.

If recommendations are auto-applied, the bid strategy on a campaign may have changed without your team noticing. The 20-minute audit catches this. Turn off auto-apply for bid-strategy recommendations specifically; they should be a deliberate decision, not a default.

Step 5. Make the switch (or do not)

For each campaign you flagged in step 2 or 3, the decision is: switch to a strategy the campaign has data for, or wait until the conversion volume justifies the current strategy.

The default fallback is Manual CPC with a tight bid ceiling slightly above the historical CPC for that campaign. Manual CPC respects the ceiling, prevents the algorithm from chasing expensive auctions, and gives the campaign time to accumulate conversion volume.

Once a campaign reaches the conversion threshold (30 for Maximize Conversions, 50+ for Target ROAS), switch back. Give the algorithm 14 days before evaluating the new strategy's performance. The first 7-10 days are the algorithm's relearning phase, and the spend is volatile during that window by design.

What this audit does not tell you

The 20-minute audit is a stage-fit check, not a full account diagnostic. It does not tell you whether your keywords are right, whether your ad copy is converting, whether your landing page is the bottleneck, whether your conversion tracking is firing accurately, or whether the campaigns are structured correctly to begin with.

If the bid-strategy audit surfaces multiple flagged campaigns, that is usually a downstream signal that the account was set up without a stage-aware strategy in the first place, and the deeper structural issues compound from there. The full audit, the one that produces the prioritized fix list, is what the Conversion Second Opinion exists to deliver. The 20-minute version is the entry; the 72-hour version is the diagnosis.

The 20-minute Google Ads bid-strategy audit.