Hi, Rick!
You hit the nail on the head! While covering just a part of the
syllabus in order to understand something may be worth little,
covering everything but without understanding is worth nothing!
One of the impediments to understanding is, in my opinion, those
encyclopedic textbooks which students do not have the time to
read. The "intelligent" way to read a scientific book is to read
for one minute and then think about 10 minutes about what you read
(construct possible examples, compare with previous sections etc.)
Greetings! Emilio