Actually, I find Robin's excellent answer to be rather contradictory. First she lists what she does, and says "the next day, I send them a Private message. If, in a week, nothing happens, I put in an Unresponsive profile manager request"
And then later in the answer, she says the part you have quoted about remembering that some people might not login every week, suggesting that it's better to hold off.
Which is it? The next day, or wait a while...
(And I'm currently looking at a UPM who hasn't been on since 2010, and another who hasn't been on since September 2017)