Assuming that a helmet has had no knocks or other damage, how often should it be replaced?
Clearly, as it is immediately at the end of it's useful life as soon as it is manufactured, let alone retailed, you should replace them continually, for ever. To get off the Helmet Wheel of Life the enlightened one recommends replacing it with a nice team cotton cap (trendy 2nd tier Italian race team from the 80's would be ideal) or a Buff, or nothing...
