Hi @autumn​ ,

Q - How would we trigger an experience based on the last time a user saw another experience?

A - You should start using Series to do this. 

Use "Last contacted" for that reason will not work, if someone from your team member sends an e-mail or in-chat response this parameter will be updated. 

You should start building the Series, more information can be found here.

Thanks for the info, @roy s11​. Is there a workaround if we don't have Series?

@autumn​ , Hm... What about launching a Mobile carousel from a button inside your app? More info can be found here.

@roy s11​ That's unrelated. The first experience we launched is a mobile carousel. We're looking to follow-up this experience with a chat message that's sent 30 days after the user sees the mobile carousel.

@autumn​ , In this case, after 30 days you can manually tag all viewers and use this tag to show the next experience. 

That's the best workaround if you not use series.

Thanks for the help, @roy s11​.