An alternative method of lecture preparation

Normally when I prepare a lecture I tend to follow the strategy:
1. Read the textbook.
2. If need be look at other books.
3.  Write a summary of the relevant part of the book.
4. Work this into a lecture.

Today I followed a different procedure.
1. Don't look at any books.
2. From memory, write out rough notes with the key ideas,  equations, and graphs that I want to communicate.
3. Look at the text to just check and polish details.
4. Rework the rough notes into "neat" notes for the lecture.

The end result was this lecture on Transport properties of metals in the Bloch model.

I think the advantage of this different approach is that it helps prevent one getting bogged down in details that are tangential to the essential points. This might be good for students because it may make the main points clearer. It is also good for me because it saves all the time I sometimes spend struggling through these minor details and worrying about whether or not to include them in the lecture.

I also found that the actual lecture flowed better because more of it was "in my head" rather than stuck in the notes. However, ultimately students should be the judge.

I welcome thoughts on this and on alternative strategies.