Yes, it is normal to have to move your head slightly. As to whether or not you will look in the mirror less that is entirely a decision that is up to you. You do get used to the mirror though. When you hear something, know you're in a tight spot, or need to turn left up ahead you will instinctively look in the mirror. I love having my mirror. Helmet mounted mirrors are nice because you can change where you're looking by moving your head slightly.