Honestly, I think this just depends on how you learn best and how much time you have. I learn best by writing things, thinking about them as I write, even saying it out loud. So I'd reannotate if I have time partially because the new book is nice and partially because I think it would really help firm some of the annotations into my mind. That said, everyone learns differently, so you've gotta figure out what works best for you. Good luck!