There are about 950 problems in the "elementary chomego", which are aimed at players from complete beginner to roughly 5k. Regular repetition of these problems has been suggested as helpful, and tracking the time in which the collection can be completed can be seen to provide one measure of one's progress in life and death.
This is line with advice commonly given by professionals, such as James Kerwin and Janice Kim, that students should focus on doing many relatively easy problems as opposed to a smaller number of more difficult ones.
It's said that once one becomes accustomed to speedrunning the elementary chomego, completion can be accomplished by an SDK within a week, and later even in one day. Several dan players claim to be able to finish it within a few hours.
(I was once told of a player who would allegedly complete the collection every morning. -- bugcat)