Cost Reality
A senior in-house search director plus one specialist costs around £250,000 per year fully loaded in most major markets. A capable agency retainer covering the same workload usually runs £8,000 to £20,000 per month. Agency wins on cost until you are spending enough to justify a full team.
Expertise Breadth
Agencies see dozens of accounts across categories. That breadth produces playbooks no internal team can match without years of trial. In-house teams see one account in extreme depth. Both have value. The right choice depends on whether you need pattern recognition or deep domain mastery.
Accountability and Ownership
In-house teams own the outcome inside the company. Agencies own the deliverable inside a contract. Both can be made to perform, but the operating model differs. In-house works best with a strong internal owner. Agency works best with a clear scope and an internal point of contact.
The Hybrid That Usually Wins
Most mid-market and enterprise brands settle on a hybrid: a small in-house team owning strategy, brand voice, and platform relationships, with an agency partner providing execution depth and cross-account pattern recognition. The hybrid model captures both speed and depth.
Frequently Asked Questions
When ad spend exceeds roughly £200,000 per month and you have an internal owner with capacity to manage the function.
Often yes for committed multi-year agreements. Less so for month-to-month engagements.
Most do during transition periods. Insist on documentation as part of any offboarding clause.
Hiring one specialist who covers SEO and PPC superficially. Specialists outperform generalists in both channels at scale.
Yes if scope is unclear. Document who owns what, then review quarterly.