How much is "enough" practice? I'm a second year EE major and just starting to get into intro to analog circuits, digital circuits/theory, and differential equations. I've decided to devote part of my time to strengthen my basics - basically do schaum's outlines/"3000 problems in [whatever]" for calculus, linear algebra, circuits, etc... The problem is, that approach takes time. A lot. And I know I'd be wasting my time doing applications of differentiation for hours considering I won't use it much - if at all - compared to integration and ODEs. \And there's the question of how far to go - for example: should I do BOTH Schaum's outline for Linear Algebra and Schaum's 300 solved problems in Linear Algebra? Should I go all the way back and even spend dozens of hours to go through 3000 pre-calculus problems? Or physics: E&M? Doing lots of problems there isn't a cake walk. There's the idea that if you're good enough, doing 100 problems should be very fast... but that's still a lot of time I could use to prepare for signals and systems maybe or do something else... Also, on a related note, plenty of the problems in texts and schaum's are just needlessly complex. I don't see them in tests and HW assignments at - or anything that looks like them. So I get the impression I'd be wasting time doing them. Anybody knows what I'm talking about... ?