My question therefore is about the jib: what are the typical early signs to look for? I used to have a very old jib made from a different weave which probably never was as stiff as the sailcloth for my current set of sails. By the time I got it, you could stuff it like a spinnaker and not see wrinkles...

Anyway, that sail clearly showed its age, because it was no longer possible to set it in anything other than moderate winds without the luff oscillating. (It was a great sail for extreme drifting conditions to the end, because it's lack of stiffness meant it would set in the lightest airs).
Anyway, so what are the "early" signs to look for that a jib has "begun to age" (as opposed to "reached the end of any conceivable life span"). I would have expected to see signs on both main and jib after about the same length of service, but while the condition of the main seems obvious to me, the same isn't true for the jib. So what should I be looking for that I am not seeing?
Or is it a "thing" that a jib can last a bit longer than a main?