In Tamil there is a proverb "Chithiramum kai pazhakkam', which means the drawing picture will come good if practice continuously.
Similarly if we sit for studying our lessons daily the fear of mugging up or preparing for examination will get reduced. Moreover, the sitting for study reduces our other unwanted activities which are normally affect us in various directions.
Some times when our friends come for chatting or outing, they will automatically move out by seeing your studying in the house.
I have seen in some houses father of the house used to sit with some books in the evening which tends the children to do get practice of sitting for their lessons whether home work is there or not.
In my house, even in our childhood, our parents never asked or forced us to sit for studying, but we every one sit for studying by seeing other brothers and sisters. My mother and aunt went sitting in the outside entrance of the house to avoid visiting neighbors which would affect our studying.
Moreover the sitting for daily study is inevitable for nowadays especially to get rid of mobiles and televisions.