Should nyloc nuts be reused after removal?

[Gnomatic]

Or replaced with new when putting stuff back together?

[slomobile]

It depends on their condition and how vibration prone and critical the nut is.

If it is a "Jesus Nut" like the nut holding a rotor on a helicopter where a single failure is life threatening, always replace it, no matter what.
I cannot think of any Jesus Nuts on a wheelchair.
Closest thing is the single bolt that holds a wheel adapter on the shaft.
Actuator nuts are fairly important. Don't want to drop your head, or foot plates into the ground. Improperly designed or built seating can cause binding in actuators to back nuts off. There should be some play in actuator mounts.
Any nuts holding the entire seating system on are important, along with anything else you consider critical to you.

Check to be sure the nuts cannot be fully put on by fingers. If it requires a tool, that is usually good enough to stop simple vibration. If they hold on something that rotates and could back them off forcibly, the standard is higher. Probably requiring new.

Nylock nuts have a total lifetime about the length of your finger. If they have been driven further than that in any direction, toss em. Especially if spun on or off long screws by a power tool. That heats them up excessively.

[Burgerman]

Never thought about the impact driver heating up the nylon. As you say as long as you cant tutn it without tools its good enough for our usage.

[Gnomatic]

Thanks for the replies!

[ex-Gooserider]

Of course if one wants to be paranoid, you can also safety-wire the critical items... Even w/o drilling the nut as required by 'proper' procedures, if you drill the bolt above the nut and run a bit of wire, or put a split pin through the hole, there is no way it can come off....

ex-Gooserider