I suspect it's much like the answer we typically give to a jump student who asks "in an emergency, how long do I have to deploy my reserve?"
Why son, you have the rest of your life.
How long do you have to get out of the traumahawk? The rest of your life.
Not all airplanes are easily exited, of course, and certainly not all are well advised.
Even in aircraft equippped with rapid egress doors, such as those held on by pins, carrying a parachute may not be the order of the day.
All ag airplanes come with jettisonable canopy doors; pull the handle, the pins in the hinges pull clean,and the door is knocked away. I don't know anyone who flies ag that wears a parachute, however, or anyone that would, in their right mind suggest it to be a good idea.
Even where we fly ag airplanes at higher altitudes, none of us wear parachutes. Most have enough common sense to know that we can fly the airplane (or what's left of it) back down.
Where aerobatics are performed, assuming they are performed high enough, one has a reasonable chance of getting clear and deploying one's canopy. Low level aerobatics, not so much.
So far as wearing or use of parachutes in light airplanes such as the venerable Cessna 172; not really a good idea. Then again, when was the last time we saw or heard of a wing come off a 172 in flight?