> The original plan was to use the fifth day for non-billable work such as searching clients, meeting with people, doing mandatory paperwork, writing blog posts, doing something that would later generate passive income etc.
That's work.
That's work.
Billing takes 5 minutes (I use web application called Zervant) and checking that the payment is received takes few minutes.
Then there are "random" stuff like updating insurance, meeting people (few times per month) etc.
Not that much stuff really.