In keeping with the subject of reflectors; Adding to what others have already said on the pro's and con's, most of the OEM reflectors on bikes really are of poor quality. That's quite sad because there are better materials out there that are way more reflective. One example is the "Reflexite" brand of reflective tape.

The OEM reflectors sold with most bikes probably cost peanuts. Obviously the government really cares or knows little about safety equipment for bicyclist. Upgraded "Reflexite" type reflective material would triple the effectiveness of the current front, rear and wheel mounted set-ups currently sold on most new bikes. Add some 3M type reflective straws to the wheels and the "see me" factor again gets multiplied. Now before someone adds, "Yeah but it won't help unless lights are shining on them"...Actually, good reflective material is WAY better than standard equipment and will gather and reflect very low levels of light. I've passed bikes parked in bike racks more that a 100 ft. off the road and could see the reflection of the 3M wheel straws 45° to the angle of my head lights. Impressed me so much I made a mental note to pick me up some by spring.

I don't use most of the OEM reflectors on my bikes. The only original reflectors I use are the wheel reflectors. Just before I posted this I did a little test on my wheels to test the effectiveness. I couldn't believe how pathetic they were. Looks like I'll be adding some 3M tape to those to boost their effectiveness. As soon as the winter is over I plan on adding some of the 3M reflective ( color matched ) tape to my frame. Even though my bike is covered with lights ( front , rear, and sides ) I figure some more reflective tape can't hurt.