I have had my Proven 6kW for 6.5 years and not have any spring break. It is fairly windy where we live and it has produced 92mWh (averaging 14.1mWh/year) in that time. I have however changed the bolts and plastic sleeves + the nylon spring inserts. (Kit from Kingspan - who now own Proven). At the same time I tensioned all the springs by moving the bolt ends out one hole.
Are you in a very windy site? The springs only stretch in very high winds...