Not really recommended to NOT go to lectures unless you can guarantee you'll self study. Even if the lecture bores you you do absorb some information. Also there are several factors which weigh on the feasibility of not going to lectures:
-Whether lecture recordings exist
-How shit or good your lecturer is
-Whether lecture notes are avaliable
-Whether the textbook covers everything in the lecture (lectures may cover things not in same order as textbook, or talk about completely different things)
-Whether you like to ask people questions to learn
-Whether you actually have the discipline and motivation to learn on your own
Other factors to consider:
-Whether you'll spend the time listening or whether you're going to read webcomics/play WoW(some people apparently cannot drag themselves out for a single straight waking hour)/IM randoms/watch porn(someone did this last year) etc
-Will you be awake?
-Whether or not attendance is marked
-How many classes occur at this time?
-Would you be better able to concentrate on the rest of your lectures if you skipped one and had lunch? (6+ hours/no breaks FTW)
Really does depend on the course and the individual.
One of my courses last year I attended the first and last lectures of + 1 in the middle for an assignment hand-in, got my highest mark for the year in that course.