Most Google Ads accounts carry structural debt. Campaigns added over years to solve specific problems - a new product line, a seasonal push, an agency handover - accumulate into something that made sense at the time but quietly undermines performance now. The problem is not the campaigns themselves. It is what happens when Smart Bidding tries to learn across a fragmented account.
Smart Bidding is a signal-hungry system. It needs conversion volume, consistent conversion data, and clear signals about what a good result looks like. Legacy structures routinely starve it of all three.
Why Structures Built for Manual Control Fail Smart Bidding
The account structures most advertisers are running today were designed for a different era. Tight keyword segmentation, one-to-one campaign-to-product-category mapping, and granular match type separation all made sense when you were controlling bids manually at keyword level. You needed that granularity to set sensible bid adjustments.
Smart Bidding does not operate at keyword level in the same way. It looks at auction-time signals - device, audience, time, query intent, competitive context - and adjusts in real time. But it can only optimise effectively when it has enough conversion data to learn from. Split that data across twelve campaigns serving similar audiences and similar intent, and each one is running on a thin slice of signal that is not statistically meaningful.
The practical consequence is that Smart Bidding either performs conservatively because it lacks confidence, or makes poor decisions based on noisy data. Neither outcome is what you are paying for.
What Counts as Redundant and What Does Not
The consolidation argument is not a licence to flatten everything into one campaign. The goal is to eliminate structural separation that serves no commercial purpose - campaigns that are split for historical reasons rather than meaningful business distinctions.
Meaningful distinctions worth preserving include different margin profiles, separate geographic strategies with genuinely different CPA targets, distinct audience strategies, or product lines where a conversion in one category is worth materially more than another. If two campaigns have different target CPAs or ROAS targets for a legitimate commercial reason, keeping them separate is justified.
Redundant separation - the kind that is worth consolidating - tends to look like multiple campaigns targeting the same intent and audience with similar bid targets, simply because someone created a new campaign rather than expanding an existing one. Or match type siloing: separate campaigns for exact, phrase, and broad against the same keywords, which made tactical sense years ago but fragments signal badly under Smart Bidding.
How to Approach the Consolidation Without Disrupting Performance
Before touching campaign structure, audit your conversion data distribution. Look at how many conversions each campaign is generating per month. Any campaign with fewer than thirty conversions in a thirty-day period is likely running below the threshold where Smart Bidding can operate reliably. That is a practical starting point for identifying candidates for consolidation.
When merging campaigns, do it gradually. Pause rather than delete the campaigns being retired, and monitor the receiving campaign closely for the first two to four weeks as bidding recalibrates on the expanded data. Expect some volatility - Smart Bidding will go through a learning period as it absorbs the new volume and adjusts. Set expectations with stakeholders before you start.
Use ad groups to preserve the thematic and creative distinctions that were previously handled at campaign level, where those distinctions do not require separate bid targets. Ad group structure can carry a lot of the organisational logic that used to require separate campaigns. The campaign layer should reflect commercial strategy; the ad group layer can handle product or messaging differentiation.
Smart Bidding and Performance Max Compound the Problem
The structural debt problem is more acute now that Performance Max sits alongside standard search campaigns in most accounts. If you are running PMax alongside legacy search campaigns targeting overlapping intent, you are potentially pulling the same user through multiple campaign types simultaneously, with each one drawing on a fragment of your overall conversion signal.
Google's own auction dynamics mean that PMax and search campaigns from the same account can compete in the same auction. If your account structure creates unnecessary internal competition, you are inflating your own costs and muddying the attribution picture. Rationalising search campaign structure is therefore not just about Smart Bidding efficiency - it is about how your entire account interacts with PMax.
This is also worth bearing in mind for accounts using AI Max on search campaigns. AI Max's expanded matching relies heavily on Smart Bidding working well, because broader query matching without strong bidding intelligence is a fast route to wasted spend. If your account structure is already fragmenting signal, layering AI Max on top compounds the problem rather than solving it.
The Structural Audit You Should Run Now
Pull a twelve-month view of your campaigns and ask three questions for each one. First: does this campaign have a distinct commercial purpose that justifies a separate CPA or ROAS target? Second: is it generating enough conversions to support Smart Bidding independently? Third: if it were merged into another campaign, would anything commercially meaningful be lost?
Any campaign that fails on all three counts is a consolidation candidate. Document your reasoning before you start making changes, both to protect yourself if performance dips during transition and to prevent the same structural drift from recurring when someone adds a campaign six months from now for reasons that are no longer relevant.
Account structure is not exciting to work on, and it rarely appears on anyone's monthly optimisation checklist. But it is the foundation that Smart Bidding sits on. If that foundation is fragmented, everything built on top of it - bidding strategy, audience signals, creative testing - is working against the grain. Fixing structure is not a tidy-up exercise. It is a performance intervention.