Just a thought, wouldn't manually specifying a schedule or interval warrant the enabling of the periodic updates as well?
It would be breaking behaviour, but it seems like a more obvious way to inerpret the command line/environment args.

It should probably also write a startup message when running in "manual" mode, with schedMessage being something like:
Waiting for manual dispatch, but that is probably outside the scope of this PR...

Originally posted by @piksel in #916 (comment)