When running a remarketing (Google favorite name) or retargeting (Meta favorite name) campaign to attract new customers (on Google Search, YouTube, or Facebook), always remember to exclude your current customers. You can select your current customers by uploading a list or defining a specific audience.
Believe me, I’ve experienced it. Nothing frustrates users more than being targeted for a product they have just purchased.
There are more effective ways to invest your money than by irritating your customers!

I experience this issue daily. I assume that, for a large company, the savings they get from excluding existing customers could be insignificant. Still, the impact on the brand should be a good enough reason to follow the best practices for remarketing.
Some marketers argue that this strategy targets existing customers to turn them into repeat buyers. This approach is certainly valid, but it requires highly targeted ads that are personalized to promote not only different products from those recently purchased but also items that complement or upgrade the original purchases.
Remarketing vs. Remarketing
Remarketing and retargeting are frequently used as synonyms, with similar meanings. In particular, Google Campaigns, regardless of the platform (Search, Display, or YouTube), are usually called remarketing, while the equivalent campaigns on Meta (Facebook and Instagram) are called retargeting.
Two words have assumed more specific definitions: remarketing is now used when serving ads to known users whose email or phone number I have in my CRM, while retargeting is preferred when serving ads to anonymous users identified mostly through tracking cookies or similar.
Over time, the two words have assumed more specific definitions: remarketing is now used when serving ads to known users whose email or phone number I have in my CRM, while retargeting is preferred when serving ads to anonymous users identified mostly through tracking cookies or similar.
SemRush defines the two terms as shown in the following image.
