I rode my bike without anything on it last year. No speedo, no tach, no turn signals, no mirrors, no tag light. Mostly it was cause I was too lazy to wire it and I wanted to ride it instead. Did I die? No. But I'll admit I felt pretty unsafe a few instances. That bike is undergoing a major overhaul this winter and I'm compromising on it somewhat. Rear turn signals are important, as is atleast one mirror. If you've got no turns or mirrors you're asking to get hit changing lanes. Fronts are less important, IMO. At 4-way stop they matter, but that's the only place. At an intersection you either have the right-of-way or not. If you've got a lot of 4-way stops instead of lights around your place you prolly oughta have front turns. There are some that clamp onto the fork tubes that are pretty decent looking and hidden. You can also get mirrors that have turn lights in them.