Switching Marketing Agencies Without Losing Ground

The decision to change marketing agencies is usually the easy part. The fortnight around the changeover is where businesses lose ground, and it is almost never the new agency's fault. It is the unrecorded knowledge that walks out of the door with the old one.

I have been the incoming consultant on more agency transitions than I can count across 13 years, and the clean switches share one habit: somebody documented what was actually working before anyone gave notice.

This is written for the owner or marketing manager who has decided to move on and wants to do it without throwing away what already works. It covers what really breaks when you switch, the asset list to build first, who owns the domains and accounts, what to keep running through the change, how to protect the pages that already rank, what to ask for in the first two weeks, how long a transition takes, and how to make the new arrangement stick.

What actually breaks when you switch

Rankings, tracking and ad history

Three things do most of the damage: a page that disappears, tracking that is rebuilt badly, and advertising history that is abandoned. Each one is a handover problem rather than a marketing problem, and each one is avoidable.

Rankings rarely fall simply because a new team takes over. They move when something technical changes underneath them, or when the work quietly stops for a few months while everybody settles in.

The quiet losses nobody notices at first

The expensive losses are the quiet ones. A redirect that was never created, a tag that stopped firing, a set of ad account exclusions nobody wrote down, a content calendar that lived in somebody's head.

Relationships in this industry are long, which means a great deal of accumulated knowledge is at stake when one ends. Per the ANA and the 4As, "The ANA (Association of National Advertisers) and the 4As (American Association of Advertising Agencies) released a joint study revealing that the average client-agency relationship tenure now stands at approximately seven years, more than double the 3.2-year average reported in 2016." When a relationship of that length ends, what is worth keeping is the working knowledge, not just the login details.

Before you decide, document what works

The asset list to build first

Build the list before you give notice, while everybody is still cooperating. It is not a report, it is an inventory: the domain and its registrar, the hosting, each analytics property, each advertising account, every tracking tag, every redirect that was created, and every campaign or page that is still live.

The list does two jobs. It tells the incoming team what exists, and it tells you what to insist on receiving before the old arrangement ends.

Separating real performance from reporting

Reporting and performance are not the same thing. A monthly deck can look polished while the only channel actually producing enquiries is one category campaign and a handful of service pages.

Go to the accounts themselves and ask what changed after each piece of work. If you cannot connect an activity to a movement in enquiries, treat it as unproven rather than successful, and protect it accordingly.

Access, ownership and accounts

Who owns the domain, the properties and the ads

Ownership should be unambiguous and in your name, not the agency's. The domain registration, the hosting account, the analytics properties, the ad accounts and the business profiles should all be yours, with the agency given access rather than holding the keys.

Where something is held by the agency, ask for it to be transferred as part of the wind-down. A domain that sits in somebody else's account is a business risk that has nothing to do with marketing.

The handover checklist in order

Sequence the handover so nothing is left dangling: obtain the access first, record the current state second, then make the change. Freeze the list of what is running, take a full export of the historical reporting, and only then begin the switch.

Doing it in that order means the incoming team starts from evidence rather than from a blank account and somebody's memory of what used to work.

Keeping campaigns running through the change

What not to pause

Do not pause the campaigns that are producing enquiries just because the agency is changing. If a category campaign is profitable, keep it running while the new team gets orientated, and change one thing at a time so you can tell what caused any movement.

The same applies to content and email. A regular send that keeps customers warm is an asset, and stopping it to tidy up the handover costs you a month of attention for no gain.

The cost of a gap in paid spend

A gap in spend is not neutral. Competitors get a clean run at your branded and category terms, quality scores and audience data decay, and rebuilt campaigns start again without the history that made them work.

If a short pause is unavoidable, keep the highest-intent campaigns live and pause the experiments, rather than the other way around.

Protecting the pages that already rank

Redirects, canonicals and internal links

The pages earning traffic are the ones to protect, and they are usually the least glamorous on the site. Before anything else changes, record what ranks, then check that the redirects, canonical tags and internal links pointing at those pages survive the transition intact.

A redirect that is dropped during a cleanup can undo years of link equity in an afternoon. Treat redirects as load-bearing, not as housekeeping.

What to deliberately leave alone

Leave the ranking pages alone unless there is a specific reason to touch them. That includes their URLs, their headings and their internal links. A new team is often tempted to rework everything it inherits, and that instinct is where easy wins get spent on needless churn.

Where a page is genuinely weak, improve it on its own merits later. The handover is not the moment to rewrite what is already working.

What to ask for in the first two weeks

Data, documents and historical reporting

Ask for the working files, not another presentation: the historical reporting exports, the tracking setup notes, the campaign structure, the list of pages and redirects, and the calendar of what was planned but not yet done.

Ask for it in writing, and ask for it early. Anything that is "coming next week" during a wind-down tends not to arrive at all.

Setting a baseline you both accept

Before the change takes effect, record a baseline on measures you and the new team both agree on: enquiries, cost per enquiry, the visibility of the pages that matter, and the spend against plan. Then review it at the same points each month.

Without a baseline recorded before the switch, every later number becomes an argument rather than evidence. A useful review of the incoming team is only possible against a starting point that was agreed while the change was still hypothetical.

How long a transition really takes

Separating change effects from normal movement

Some movement after a switch is normal and has nothing to do with the new team. Seasonality, a competitor's campaign, a search engine update and the ordinary wobble of any account all move numbers.

To tell them apart, keep the baseline visible and watch the trend rather than any single week. If the measures you agreed are flat or improving while nothing technical broke, the transition is doing its job.

When it is fair to judge the result

Give it a full quarter. That is the shortest period that covers a normal seasonal cycle and produces enough data to compare. Per the 4As and ANA 2025 tenure report, "A joint study by the 4As and ANA reveals that the average client-agency relationship tenure has more than doubled since what was reported in 2016, now standing at an average of 7 years." A seven-year relationship is not rebuilt in a fortnight, and judging one on a fortnight's data serves nobody. The same research is clear that arrangements differ by type, since per the ANA and the 4As, "Integrated full-service agencies report an average tenure of 87 months (7.3 years), while media-only agencies have a significantly shorter average tenure of 44 months (3.7 years)".

Making the new arrangement stick

What is worth keeping from the old agency

Not everything the old agency did was wrong, and the parts that worked are worth naming out loud. The campaigns that were profitable, the content that ranks, the process that suited your business, the reporting rhythm your team actually read.

Handing that list to the new team is the difference between a reset and a rebuild. It is also the clearest signal of what you will judge them on. Research on how these relationships last puts it plainly: per the ANA and the 4As, "Independent agencies report longer AOR tenures (7.3 years) than holding company agencies (5.8 years)."

Reviews, rhythm and clear expectations

Set the review rhythm on day one: what you look at each month, what a quarterly review covers, and who owns each decision. Then hold it, because a rhythm that slips in month two rarely returns.

Where the wider question is which model suits a business of your size, consultant and agency models compared sets out the trade-offs. If you want an audit of what is working before you move, that is a sensible first step, and where the change is really about resetting the strategy after the change, that is a separate piece of work. The questions owners ask before switching cover the rest of what comes up in the fortnight around a handover.

Frequently asked questions

How long does it take to switch marketing agencies?

The access and account handover can be done in days if the outgoing agency cooperates. Rebuilding measurement takes longer, and it usually takes a full quarter before you can judge the new arrangement fairly, because that is the shortest period that covers a normal seasonal cycle and gives you enough data to compare.

What should we ask for before the old agency stops working?

Ask for the asset list rather than another report: who owns the domain and hosting, which analytics and advertising accounts exist, what tracking is in place, which redirects were created, and what campaigns or content are still live. Where you can, get the access before you give notice rather than after.

Will switching agencies hurt our rankings?

Not by itself. Rankings tend to move when something technical changes, such as a page disappearing, a redirect being missed, tracking being rebuilt badly, or work simply stopping. Those are handover problems, and they are avoidable if the transition is run deliberately.

Should we pause Google Ads while we change over?

Pausing rarely helps. If campaigns are profitable, keep them running while the new team gets orientated, and change one thing at a time so you can tell what caused any movement. A gap in spend also hands competitors a free run at your branded and category terms.

What if the new agency wants to rebuild the website?

Treat that as a separate decision with its own plan. A rebuild during a handover mixes two large changes together, and if performance drops you will not know which one caused it.

How do we know the new agency is doing better?

Set the baseline before the switch, on measures you both agree on, and review it at the same points each month. Without a baseline recorded before the change, every later number becomes an argument rather than evidence.