Simply, when one starts procrastinating without bounds.
Due date is made so that you can do it on the day it is due.
It doesn't matter whether weekend is there between the present and the due date: weekends are for partying
It does not matter how far back the due date is pushed; you just do it on the due date.
You are not a true procrastinator if you do not do it on the day it is due.
A paper is due 7:00 am, on Friday
you start it on 1:00 on Friday.
That is Lizzy K phenomenon