I've often wondered this question as well. I mean, if you have the textbook you need available at the school library and at home and you like to study both places, then which context would you use, @home or @library?
If you mostly study at home then I would recommend @home.
If you don't really study in any one particular place, but need a mobile resource, then give it a name as a context. Eg @schoolbag, or @ipad or @iphone.
I have a context @Dell, for when I'm working with my Dell laptop, which could be anywhere. Since that is heavy enough to carry, I've made a committment to not carrying texts around, and leave them in one place, so I keep my study texts only at home and so studying type actions would be @home. However if the documents are electronic and on my computer I would use @Dell.