I did none at all, regrettably. Hence only achieving ABC. If you value your future, you will do as much as you can. Take this advice from experience.
I always lack the darned time to and then am so tired in the evenings, i just don't know whether i have the emotional strength to look at something seemingly useless about succession on bloody sanddunes.
I don't know for each but overall a few hours. I tend to want to do work in school and try not to do as much after; because I like to de-stress a little.