Going through variations when playing through master games

I recently acquired a whole bunch of chess books/games collections---- do you guys recommend going over all the lengthy 10 move side variations of those GM games? Usually I tend to skip them and only do them if its like 5 moves or less (that way i can sort of envision the resulting position without having to move the pieces)

Or if your visualization skills are not yet up to par you could just cheat and use several boards.  I use a regular size board and pieces for the main line and then I have a 12" magnetic folder (glued, doweled, and duct taped permanently open) for the variations.   And yes I have been known to use a 7" magnetic folder (similarly duct taped open) for variations within variations.  I'm working on visualization but right now it's what I have to do if I want to follow games without getting lost and frustrated.