It really depends on how far out from the concepts you are and what your baseline is already. I took mine almost 1.5 years after I graduated, so 3.5 years out from any real math class. It took me a few months of sporadic studying to relearn the math concepts but after that it was fine. I would recommend really focusing on the vocab though because there is never a shortage of words to learn. Also, consistency is way more important than anything, so as long as you are setting aside the time each day/week you'll be solid. I reviewed vocab flash cards for 10-20 minutes before bed each night and it helped a lot.