Hi there, I am not KA staff, but the excellent thing about Khan Academy is that it is completely self-paced.  You are perfectly free and able to set perosnal goals for yourself for any class/quiz or unit test.  What I would recommend, is taking a look at the whole course you are doing or courses if it is more than one and seeing the best way you could divide it up to help with time management.  You could try doing a few lessons a day, or even one lesson a day if you are very busy, and see after a while if that strategy works for you 

hi! one thing that helped me was breaking my study time such as studying 25 mins and then takes a 5 minute break. Setting a goal would also help, like finishing an unit and then go for a break.