How do I upgrade from free to Pro mid-cycle?

One caveat for larger communities: keep an eye on the indexes. At a few thousand rows the difference is night and day.

This is the answer I wish I had found six months ago. Would have saved me a weekend of trial and error.

Adding a small note: the same idea applies on mobile, just with a bit more attention to tap targets.

Following this thread closely. We are about to face the exact same decision and the replies here are gold.