There's an optimization in Google Ads that takes about five minutes to set up, works on virtually every account with enough traffic to generate a remarketing list, consistently delivers conversion rates 2-4x higher than standard search traffic, and is missing from the majority of accounts we audit. It's not a new feature, it's not complicated, and it doesn't require a budget increase. It's adding your remarketing audience to your existing Search campaigns in observation mode so that when someone who's already visited your website searches again on Google, you can bid more aggressively to make sure they see you.
Most people associate remarketing with Display ads, the banner ads that follow you around the internet after you visit a website. That’s one form of it, and it’s been around for years. But remarketing on Search is different and far more powerful because you’re not interrupting someone while they read an article, you’re catching them at the exact moment they’re actively searching for the thing you sell, and you already know they’ve been to your site before. That combination of active intent plus prior familiarity is the highest-converting traffic you can buy in Google Ads, and the reason most accounts don’t have it set up is simply that nobody took the five minutes to configure it.
This post is part of our 12-point Google Ads audit. We check audiences and remarketing as step 12, the final step, because it builds on everything else in the account. Remarketing doesn’t help if your conversion tracking is broken, your landing pages don’t work, or your bidding strategy is wrong. Once all of that is sound, layering remarketing onto Search is one of the fastest performance improvements available.
Why Past Visitors Searching Again Are Your Best Traffic
Consider what it means when someone who previously visited your website goes back to Google and searches for something you offer. They’ve already seen your site, they already have some awareness of who you are and what you do, and now they’re searching again with intent to take action. Maybe they visited your auto repair shop’s website last week while comparing options, and today they’re searching "brake repair near me" because they’ve decided to get the work done. Maybe they looked at your accounting firm’s services page in January and now they’re searching "CPA near me" because tax season is here and they’re ready to hire someone.
These people are fundamentally different from someone searching the same terms who has never heard of you. The cold searcher is comparing multiple options, reading through several results, and making a decision from scratch. The returning visitor has already done some of that research, already formed an impression of your business, and is now searching again because they’re closer to making a decision. The data reflects this consistently: remarketing audiences on Search campaigns deliver 200-400% higher conversion rates compared to the same campaigns without audience layering, and they typically convert at 50% lower cost per acquisition because fewer clicks are needed to generate each lead.
How Observation Mode Works
The reason this optimization is so simple is that you don’t have to create new campaigns, write new ads, or change your keyword targeting to use it. You add your remarketing audience to an existing Search campaign in what Google calls "Observation" mode, which means the campaign continues to show ads to everyone who searches your keywords (nothing changes for cold traffic), but you can now set a separate bid adjustment for people on your remarketing list. If a returning visitor searches one of your keywords, the system bids higher for them automatically, making it more likely your ad shows in a top position for that specific person.
A typical starting point is a +20-30% bid adjustment for your "All Visitors" remarketing list. If your normal max CPC bid would be $5, the system bids up to $6.50 for someone who’s been to your site before because the conversion data says they’re worth the premium. You can get more granular over time by creating segmented lists (visited the contact page but didn’t convert gets a +50% adjustment, visited the homepage only gets +15%), but the simple version of adding all visitors with a moderate boost produces measurable results from day one.
If your campaigns run on Smart Bidding (Maximize Conversions, Target CPA, Target ROAS), the manual bid adjustment doesn't apply the same way because the algorithm controls bids. But adding the audience in Observation mode still matters because Smart Bidding uses it as a signal. The algorithm sees "this person is on the remarketing list" as one of the contextual factors in its real-time bid decision, effectively giving returning visitors a built-in advantage in the auction without you needing to set a specific percentage. You're giving the algorithm better information about who's likely to convert, and it uses that information automatically.
Broader Keywords Become Viable for Known Visitors
One of the more interesting applications of RLSA (Remarketing Lists for Search Ads) is that it changes the math on keywords you’d normally consider too broad or too informational to bid on. A keyword like "how much does a new furnace cost" is informational intent from a cold searcher, someone early in their research who probably isn’t ready to buy today, and bidding on it with standard Search usually produces a high CPA because the conversion rate is low. But when the person searching that same query has already visited your HVAC company’s website and looked at your installation page, the intent is completely different. They’re not casually researching anymore, they’re comparing prices before making a decision, and they already know who you are.
Some accounts create a separate campaign that only targets remarketing audiences (Google calls this "Targeting" mode instead of "Observation" mode) with broader keyword sets that would be too expensive for cold traffic. You’d never bid on "kitchen remodel ideas" for everyone who searches it, but for someone who already visited your remodeling company and viewed the portfolio page, that search might be worth capturing because they’re probably planning the project they looked at on your site. The economics work because the conversion rate for known visitors is high enough to justify the click cost on broader terms.
This is an advanced application that requires enough remarketing list volume to sustain its own campaign, so it’s not where you start. But it illustrates why remarketing on Search is more powerful than most people realize. It’s not just about bidding higher on existing keywords, it’s about unlocking traffic you couldn’t profitably access without the audience signal.
Excluding Existing Customers
The flip side of bidding more for past visitors is bidding less (or not at all) for people who’ve already converted. If someone already submitted your contact form, already became a patient, already made a purchase, you probably don’t want to keep paying for their clicks on your acquisition campaigns. Without exclusion lists, a meaningful percentage of your ad spend goes to people who are already your customers clicking your ads when they search for you, which shows up as conversions in your data but isn’t actually new business.
Customer exclusion is built from the same remarketing infrastructure. You create an audience of people who visited your thank-you page (or triggered a conversion event), and you exclude that audience from your non-brand acquisition campaigns. Now your budget only goes to people who haven’t converted yet, which lowers your true acquisition cost by removing the repeat visitors who inflate your numbers without generating new revenue.
For businesses with Customer Match capability (you can upload email lists), exclusions get even more precise. Upload your active customer list, let Google match it against their user base (typical match rates are 29-62% depending on data quality), and exclude those matched users from your new-customer campaigns. This is particularly valuable for subscription businesses, memberships, and any service where existing clients might search for you again without needing to be re-acquired through paid ads.
The List Size Barrier Just Dropped
Until December 2024, remarketing lists on Search campaigns required 1,000 active users to be eligible for targeting. For smaller businesses with modest website traffic, hitting 1,000 users within the list’s membership window was a real barrier that kept RLSA out of reach. A local business getting 200 unique visitors per month with a 30-day membership window would never accumulate enough users to activate the feature.
Google dropped the minimum to 100 users across all networks in late 2024, with full rollout completed by early 2025. This makes RLSA accessible to virtually any business running Google Ads with a functional website. If you’re spending money on Search and getting clicks, you almost certainly have 100+ users in a 90-day remarketing list. The barrier that used to keep smaller advertisers out of this optimization no longer exists, which makes it even more notable when we audit accounts and find no audience layers applied to Search campaigns.
For accounts that were previously below the threshold, the fix is straightforward: ensure your Google Ads remarketing tag is installed (or link your GA4 property to Google Ads, which shares audiences automatically), set the membership duration to 90 days to build enough volume, and add the list to your Search campaigns in Observation mode once it reaches 100 users. The whole process takes less time than reading this post.
How to Check Yours
In your Google Ads account, click into any Search campaign and look for "Audiences" in the left navigation. If you see audience segments listed with performance data next to them, remarketing is already applied to that campaign. If the section is empty or only shows demographics, no remarketing audiences have been added and this optimization is available to you immediately.
If audiences are applied, check two things. First, are they in Observation mode or Targeting mode? Observation mode is what you want on most campaigns because it adds the signal without restricting reach. Second, check the performance data on the audience segment. Compare conversion rate and CPA for users on the remarketing list versus users not on it. If the remarketing audience converts at 2-3x the rate (which is typical), that confirms the optimization is working and you might consider increasing the bid adjustment to capture even more of that traffic.
Also check whether you have any exclusion audiences applied. If your non-brand campaigns don’t exclude past converters, a portion of your acquisition budget is going to people who already became customers. The size of that waste depends on how much repeat traffic your brand generates, but on accounts with strong organic presence or active customer bases, it can be 10-20% of non-brand spend going to people who don’t need to be re-acquired.
If your agency has never set up remarketing audiences on your Search campaigns, never discussed observation mode bid adjustments, and never implemented customer exclusions from acquisition campaigns, those are three optimizations available right now that require no additional budget and typically improve performance from the first week.
If they can't explain why those aren't configured, that's worth a conversation about what "management" actually includes.
This is one of the 12 steps in our full Google Ads audit process. If you want us to evaluate your audience setup and show you what remarketing on Search could do for your account, request a free audit and we’ll run the analysis.
