[WalterSear]

Rebase is best done before you share commits with anyone.

I routinely do an interactive one before PRs to clean things up.

[recursive]

Is there a reliable way to know whether any of the involved commits have been pushed anywhere? I would probably usually know off the top of my head, but not always.

[rakoo]

Check your local branch and the associated remote branch in your git log.

If the remote branch is an ancestor of your local branch, you have some commits that haven't been pushed yet and you can "play" with them.

If the remote branch and the local branch point to the same, you can't rebase without potentially impacting someone else.

If the remote branch and the local branch have diverged, it's already too late.