In article ,
Simon Kahn wrote:
Not shooting, just buzzing....
Not Government but BGA Laws &Rules:
Parachutes
RP16.
..The owner should ensure that it is checked regularly
by a competent authority. The interval should not be
greater than three months or the manufacturer's recommendation,...

Yep, in the US that would be 60 days, since some natural fiber chutes
require this. The "or the manufacturer's recommendation" gives
huge leeway...

www.butlerparachutes.com/repack.htm

gives some insight here...