A competitor's longest-running ad is the one they have kept paying for the longest. Nobody funds a losing ad for months, so it is the closest thing to a proven winner you can see from outside their account. Finding it takes ten minutes on Meta, two on Google, and a diary on LinkedIn.
On Meta
- Open the Ad Library, set the country, choose "All ads", and search the brand. Pick the page that is actually theirs.
- Filter to active ads. In the filters, sort by start date, oldest first, or just scroll to the bottom: the library shows a "Started running on" date on every card.
- Open the oldest active ad. Note its start date, its format, and the message. Then look at how many other active ads share that message. One old ad on its own is a leftover; one old ad with five younger cousins is an angle the brand has found and keeps iterating.
What you can also see: whether the ad runs on Facebook, Instagram or both, and, for ads shown in the EU, a reach range.
On Google
- Open the Ads Transparency Center and search the advertiser. Verified advertisers show up by name; if you cannot find them, try the parent company.
- Each ad shows "first shown" and "last shown" dates. Sort by first shown, oldest first.
- Search ads have no hook to read, so read the offer: what is promised, what is discounted, and where the ad sends people. The oldest live search ad is the offer that has converted longest.
On LinkedIn
There is no shortcut, because the library publishes no dates for most ads. Look the company up in the LinkedIn Ad Library, save the list of ad ids with today's date, and repeat weekly. After a month the ad that has appeared in every snapshot is your longest runner, with a run length that is a lower bound. The library's search does accept a date range, so if you are patient you can bound an ad's first appearance to a two-week window by searching backwards. We wrote up what the LinkedIn Ad Library does not show in full.
What the longest runner tells you
The angle, not the ad. Do not copy it. Read what it promises, to whom, and with what proof, and ask whether your product can make a stronger version of that promise or a different one to the same person.
The format the platform rewards for this brand. A static that has run for a year while the videos around it churn is a finding about the audience.
The floor for your own tests. If their proven ad has run 300 days and your best has run 20, you do not yet have a winner, you have a candidate.
Where the run length came from. A published Meta start date is a fact. A Google first-shown date is a fact about when Google first served it. A LinkedIn number you reconstructed is a bound. Keep the label on the number when you put it in a deck, or someone will treat a lower bound as a point.
The weekly version
Doing this once is a morning. Doing it every week for a competitor set of ten, across three platforms, is the job nobody keeps up with, and the LinkedIn diary is the first thing to go.
MessCube keeps the diary. It reads every ad reaching your audience on Meta, Google and LinkedIn, records when each was first and last seen, shows the longest run per advertiser and per angle, and labels every number by where it came from. The market read is $39 a month, and the free ad longevity checker answers for any single ad link you paste, no sign-up.