Why re-reading feels like progress
Reading a chapter I've already read once is easy. Everything feels familiar, which my brain quietly interprets as "I know this," even though familiarity and actual recall are not the same thing at all.
The PYQ set that changed my mind
I sat down convinced I had Discrete Mathematics under control after two full read-throughs of my notes. The PYQ set that followed said otherwise — I got barely half of the graph theory questions right, on a topic I'd have rated myself confident in five minutes earlier.
What I do differently now
Every topic gets a PYQ set within a day or two of the first read-through, not weeks later. If I can't solve the problems, the notes weren't actually learning yet, just reading.