Businesses which stop advertising once they start ranking highly for specific terms are abandoning a whole group of prospects.
Recent research shows that over a third of adverts in the Google results are for websites that already rank in the top 10 organically for the same keyword. This indicates that a significant portion of businesses are paying for ads when they already have visibility for that term.
For many of us (as well as all those advertisers above) that will make perfect sense. Pay-per-click ads can complement organic rankings by bringing the advertiser ‘above the fold’ where the organic result isn’t immediately visible without scrolling. On branded terms, they’re probably quite cheap. They can also force out competitors.
It’s also been shown that many search engine users don’t go any further than the first 2 or 3 results (which are ads), while a similar number scroll past the ads and start with the organic listings. So businesses which stop advertising once they start ranking highly for specific terms are abandoning a whole group of prospects. It still makes sense to advertise and continue SEO efforts.