What's an "academic hour" when it's at home? It depends on what academic institution's representative you ask. And some places, Universities, mostly, have longer periods of tuition than an hour, often 90 minutes. But in a 90 minute lesson, most teachers would break it down with changes of pace and activity after an "academic hour", doing something else.
Which lasts between 40 and 50 minutes, but sometimes it's an actual hour. One of the reasons we have this is that after an academic hour, students need to get to another classroom, or the teacher does, and you give them 10-20 mins to do so, (5 minutes in some places, regarded as stingy). Also, attention spans for learners tend to be a few minutes either side of three quarters of an hour.
So when I say "Day 9" on the Lincolnshire Poacher, I mean I've done an academic hour of practice, warming up with scales, probably, so say 15 mins of that, 30 with The Poacher. But because I am my own academic institution, my academic hours are flexible, going from a minimum of 40 mins, up to the full hour, and sometimes beyond.
I'm keeping a careful note of how much I practice in this blog, but I don't want to get obsessive. So I can say that as of today, I've spent 9 academic hours on The Poacher, with two hands. Which someone standing over me with a stopwatch would probably say is more like 7 actual hours.