Sure... but also while you're sitting there doing challenging problems, mix them up... rather than just doing trig problems, alternate a bit of trig with bit of

Sure... but also while you're sitting there doing challenging problems, mix them up... rather than just doing trig problems, alternate a bit of trig with bit of square equations, etc. That way you'll tire less quickly and retain more. That's what this article is about, not that there's a better method than sitting and doing challenging exercises.