I've been thinking and trying to come up with a single most efficient way of tracking my study of life and death. As I know it, reviewing problems that one has gotten wrong a number of times in a timed manner is ideal. This also leads to "hard-wiring" - a term that I've read elsewhere in L19.
The problem I face is that which comes from reading too many books at once. When I put one down for too long and try to come back to it, I lose track of the sense I had of how much of the book I've completed and I become extremely tempted to just start from the beginning again.
When you are studying Life and Death problems from a book, how do you keep track of your progress? Do you mark your attempts directly in the book? Do you date those attempts? Do you review the book in full afterward, pulling problems marked wrong, or do you keep a separate notebook? What do you write in that notebook?