I think you may find it's a manufacturere stipulated thing (at least in
some cases), like a TBO on engines in powered airplanes.

At 00:31 06 July 2011, Scott Alexander wrote:
Check EBay they have some good parachutes listed from time to time.


My sister and her husband are both parachute riggers. They both repair
old parachutes. I asked them last week over dinner the same question
you are asking. Both said that as long as a parachute is still in good
condition and will pass the repack inspection, not to worry.

Buy an old parachute of eBay and use your extra cash for other glider
stuff.