Given that he lives in Tokyo, which has one of the highest costs of living on the planet, I guess that's an important point as to HOW fantastic his success has been :)
"Appointment Reminder’s key stat of interest is monthly recurring revenue on our publicly available plans, since this is the most predictable revenue in any of our businesses and thus lets me make consequential decisions like “Move the family to Tokyo, where rents are 5X what they were in Ogaki” (that happened, more later” or “Bring on help” (that also happened, more later)."