ed, for protexctng springs; get a bike inner tube, cut to length of spring, cut down middle, wrap around then secure with 'hockey' or plumbing tape. As for springs braking, yes they have a finite life.
This is a new sport so not many have hade p-j's for long, so how long they last is difficult to say ( months owned or hours bocked?). I know peeps with the same springs a year on, I also know a few peeps who have springs 2 x's above designated wieght for there size who can pound springs to pieces in 2-3 months. But those guys are pro/semi pro and I tell you ive seen them hammer it , you would quite understand them braking so quickly.
What happens when a spring breaks? You here a 'snap' bit like a twig braking and then the spring gradually looses 'bounce' and u get a spring loaded limp ( actually this happened to a m8 of mine today ---there may be some video shortly). Dont think there will be a sudden colapse with you falling to the ground at speed.
However, as for my friend he was using a pair of replacement 'carbon fibre' springs about his 4th set! There does seem to be a problem with the high/upper weight range - they seem to be strong but brittle.
Oh and it is difficult to get carbon fibre springs in this county ---he aquired them via the erm 'grey market'
