What's the cost of switching Google Ads agencies?

The cost of switching is almost always smaller than brands assume, and the cost of not switching is almost always larger. The framing 'switching is risky' often hides the fact that the current setup is leaking material profit every month.

Direct fees are usually minimal. Most reputable agencies do not charge a separate onboarding fee: the first month's retainer covers setup. Some charge an audit fee that gets credited against the first retainer. Outright onboarding fees beyond a few hundred pounds are uncommon and worth questioning.

Transition dip is real but bounded. Expect 2-4 weeks of noisier-than-usual performance as bidding retrains on any structural changes. On a £20k/month account, the realistic worst-case dip is roughly £2-4k of margin during the transition window: recoverable within the first three months of the new engagement if the audit was honest.

Internal time is the underrated cost. Plan for 10-20 hours of senior commercial time during the handover: data hand-over, access transitions, briefing the new agency on context the old one had absorbed. Not painful but worth scheduling.

Notice period overlap is the last direct cost. If the old agency is on 30-day notice and the new agency starts immediately, you are paying both for one month. Plan accordingly or stage the start date.

Against these, the cost of staying with an under-performing agency at £20k/month is often 10-25% of margin compounding monthly. The arithmetic usually favours switching by a wide margin.