We tend to forget complicated things

One con­sis­tent pat­tern I’ve no­ticed in study­ing math is that, if some ma­te­rial feels very difficult, then I might re­mem­ber it in an up­com­ing exam, but I will al­most cer­tainly have for­got­ten most of it one year later. The suc­cess story be­hind per­ma­nent knowl­edge gain is al­most always “this was hard once but now it’s easy, so ob­vi­ously I didn’t for­get it” and al­most never “I suc­cess­fully mem­o­rized a lot of com­pli­cated-feel­ing things.”

I think this also ap­plies out­side of math­e­mat­ics. If it’s roughly cor­rect, then the most ob­vi­ous con­se­quence is to adapt your be­hav­ior when you’re learn­ing some­thing. Pro­vided that your goal is to im­prove your un­der­stand­ing per­ma­nently by un­der­stand­ing the ma­te­rial con­cep­tu­ally (which, of course, may not be the case), ei­ther study un­til it gets easy, or de­cide it’s not worth your time at all, but don’t stop when you’ve just barely un­der­stood it.

I’ve vi­o­lated this rule many times, and I think it has re­sulted in some pretty in­effi­cient use of time.