Does each "Deploy Preview" stay available forever?

Hey @benwinding,
Yes, Deploy Previews live forever! Here’s a blog post by our own Phil Hawksworth that says a bit more about the feature and how we think about it:

I mentioned earlier that all deployments are immutable and live forever. That means that each one can have it’s own URL which you can access to see that deployment.

Having permalinks for every deployment is huge. It immediately unlocks the ability to share the state of any version of your build with the testing team, the client, anyone. “What did the site look like at v3.2.14? Ah here it is.”

Deploy Previews don’t get deleted when you merge a branch and they don’t contribute to your bill. They do, however, go away when you delete your site.

It looks like you’ve already done a bunch of research on this, but sharing this post about controlling when deploy previews are generated, just in case:

I hope that helps! If you still have questions, let us know and we’d be happy to try and find answers for you.