The Short Answer
For most UK businesses spending £3k-100k/month on Google Ads, an agency provides better value — you get a team of specialists for less than the cost of one senior in-house hire. In-house makes sense at £100k+/month when you can justify a dedicated PPC team.
Side-by-Side Comparison
| Factor | In-House | Agency |
|---|---|---|
| Cost | £40-70k salary + NI + benefits + tools (£55-100k total/year) | £12-30k/year for management fees |
| Expertise | Single person's knowledge; may lack breadth across campaign types | Team of specialists with cross-account learnings and Google Partner resources |
| Speed of Execution | Fast for day-to-day changes; one person = one capacity | Dedicated resource with team backup; may have response time SLAs |
| Scalability | Requires hiring more staff as spend grows | Scales naturally; agency handles increased complexity |
| Business Knowledge | Deep understanding of business, products, and customers | Needs onboarding; may never match in-house product knowledge |
| Tool Access | Must purchase tools separately (£200-500/month for decent stack) | Typically includes tools in management fee |
| Accountability | Direct control and daily oversight | Contractual obligations; can be replaced if underperforming |
| Fresh Perspective | Risk of tunnel vision after months/years | Cross-industry learnings; objective outside perspective |
Detailed Pros and Cons
In-House PPC
Advantages
- +Deep understanding of your business, products, and customers
- +Immediate availability for urgent changes
- +Full control over strategy and execution
- +Easier alignment with sales and marketing teams
- +Can handle non-PPC tasks (SEO, social, etc.)
Disadvantages
- -Higher total cost (salary + NI + benefits + tools + training)
- -Single point of failure — holidays, sick days, resignation
- -Limited perspective — one person's experience
- -Recruitment challenges — good PPC talent is scarce
- -Training and development costs and time
- -No benchmark data from other accounts
PPC Agency
Advantages
- +Team of specialists with diverse experience
- +Lower total cost for most spend levels
- +Access to premium tools and Google Partner resources
- +Cross-account learning and industry benchmarks
- +Scalable — grows with your needs
- +Easy to switch if performance drops
Disadvantages
- -Less business context than an internal hire
- -Shared attention across multiple clients
- -Potential communication lag
- -Less control over day-to-day execution
- -Onboarding period to understand your business
Cost Comparison: In-House vs Agency
In-House PPC Manager (Annual Cost)
- Salary: £35,000 - £55,000
- Employer NI & pension: £5,000 - £8,000
- Tools & software: £2,400 - £6,000
- Training & development: £1,000 - £3,000
- Management overhead: £3,000 - £5,000
- Total: £46,400 - £77,000/year
Agency Management (Annual Cost)
- Management fees: £12,000 - £30,000
- Tools: Included
- Training: Not applicable
- Total: £12,000 - £30,000/year
For most UK businesses, an agency costs 50-75% less than a dedicated in-house hire while providing access to a team rather than a single individual.
Decision Framework
Choose In-House If...
- Ad spend exceeds £100k/month and warrants a dedicated team
- Your product/service requires deep specialist knowledge to market
- You need PPC integrated tightly with a broader marketing operation
- You have budget for a senior hire (£50k+ salary)
- PPC is a core competency you want to build internally
Choose an Agency If...
- Ad spend is £3k-100k/month — agency is more cost-effective
- You want immediate access to expert-level management
- You can't afford the total cost of a dedicated in-house hire
- You want flexibility to scale up or down without HR complexity
- You value cross-industry expertise and benchmarking data
Consider a Hybrid Approach If...
- You have in-house marketing staff who could learn from agency guidance
- Your spend is growing and you're planning to build an internal team
- You want strategic direction from experts with execution done internally
- You need specialist help for specific campaign types (e.g., Shopping, PMax)