this is just my opinion, but I feel like there should be a "reset" button, or some kind of "clear progress" option. for returning learners i think this would be particularly useful because they are able to restart at the level of knowledge they posses currently and not end up working through things they no longer know how to do.

for example: i recently re-logged in after two years to study for a math test i need for graduation. but because i have leftover progress in certain sections of the math center i an unable to keep track of what i am currently practicing.