>"but it's much harder to let that same network know that you're no longer interested for whatever reason." Yes and no. As a best practice, for a SaaS product

>"but it's much harder to let that same network know that you're no longer interested for whatever reason." Yes and no. As a best practice, for a SaaS product I marketed I would always build exclusion lists (ideally ones that auto-updated based on syncing with our funnel data) to stop showing ads trying to get people to buy who were already paid subscribers. eCommerce obviously has different challenges, and the effort to create those synced exclusion lists may not actually be worth the performance improvement at scale. But it is certainly possible when an advertiser has both sales data and ownership of the retargeting lists.