I have a TV in my living room and one in my bedroom, each with a Rogers box. If I never have both TVs on at the same time, do I still need a box for each one? Neither of my Rogers boxes are HD
Unless you're planning to constantly move one box between TVs, yes you do in order to get all the channels you're paying for.
Rogers is moving away from analog broadcasting, which means if you don't have some form of digital converter between the wall and the TV, you'll get maybe 20 channels and, eventually, you'll get nothing.