Quick answer
Start with intent themes and business outcomes, not a giant list of keywords. Separate themes when the searcher's problem, offer, landing page or economics are materially different.
The right structure is the smallest one that gives you useful control over budget, messaging, negatives and reporting. Too little structure hides important differences; too much creates noisy data and maintenance overhead.
What I would check first
I would map the core services or products to search themes, then inspect which themes currently share a landing page, conversion action and sales process. If those elements differ, the themes probably should not be forced into one reporting bucket.
I would also review search-term quality, location settings, conversion definitions and whether budget is being consumed by the highest-value intent.
Decision framework
Create a separate campaign or ad group only when at least one of four things changes: intent, offer, landing page, budget priority or measurement requirement. If none changes, splitting usually adds complexity without adding insight.
For a local service business, emergency demand, planned replacement and educational research may need different messaging and follow-up even when they share a broad category.
Real-world example
A roofing company might separate storm damage, roof replacement and inspection searches. Storm damage can justify urgent language and call-focused tracking, while replacement searches may need a longer-form estimate page and a different lead qualification process.
The value of the structure is not the labels. It is the ability to see whether each intent theme produces useful customers.
Implementation steps
Build a simple intent map, assign one primary landing page per theme, define the primary conversion, write ads that mirror the problem and create a negative-keyword process before launch.
After launch, review search terms and qualified outcomes by theme. Merge themes that behave the same; split themes only when the business decision truly differs.
Common mistakes
Common mistakes include one campaign for every keyword, mixing branded and non-branded intent without a reason, using one generic landing page and reporting only on click-through rate.
Another mistake is changing structure and bidding simultaneously, which makes it difficult to know whether performance changed because of the account design or the optimization strategy.
Measurement and business implications
Report spend, qualified conversion rate, cost per qualified lead, close rate and customer value by intent theme. The best structure is the one that improves decision quality and resource allocation.
Use the Google Ads Performance Calculator, Search Ad Builder and negative-keyword guide alongside this article.