Originally Posted by
Monster Pete
It is indeed your personal choice, but please don't just take a helmet's protection for granted- they are designed to do less than you might think. For example, they are not designed for a collision with a motor vehicle- they are tested only for a simple fall onto the ground at zero speed.
FWIW, some interesting info on bicycle helmet testing, standards, and limitations:
Snell standards:
http://www.smf.org/stds
US Consumer Product Safety Commission testing standards:
http://www.cpsc.gov/businfo/regsumbicyclehelmets.pdf
http://www.bhsi.org/testing.htm
See section 5. Not exactly zero speed.
http://www.bhsi.org/limits.htm
http://cyclehelmets.org/papers/c2023.pdf