Hey Dogperson, that's a good point. It depends on what you're looking for. If you practice two hours a day, you will make very fast progress on the piano. I can't necessarily recommend a particular time per day because everyone's situation is different. For instance, for the first 10ish years I spent learning the piano, I only practiced a half hour a day. The reason I progressed so far was because I was extremely consistent with that half hour. But obviously, if you want to make faster progress and can remain consistent, an hour to even three hours a day will give you those results.
Keypeg, thanks for checking it out, I appreciate you taking the time.... You're right, there isn't too much info in the first lesson, mostly about how much to practice for certain timelines, etc. I do address all of the rest of the questions in the following lessons though.
You're right that an unfocused 2 hours of practice can be a disaster. I would say this was the case with myself as well. With my in-person students, I would rather have them do two 15 minute sessions where their mind is fully involved and they have specific, clear-cut goals, than one 2-hour session, even if it doesn't "look" as impressive.
And while you do "consolidate" the memories of what you practiced during your sleep at night, you're right that you learn while practicing. If you didn't all you would need to do is sleep all day to become a Beethoven! I just wanted to clarify that since most people spend so much attention on practicing and so little on their sleep quality.