@terziyski Thanks! I guess I wasn't asked for it in the Tether app, and haven't been asked for it since, because I was already logged in once I'd set it up. It's not obvious, and I can see people...

I've just set up a TP-link range extender, and as part of the process, I was asked to "Create a local password to manage my device". What on earth is that for, and when would I need to use it?