I'm in favor of cheap assembly hardware for anything that will come back apart.
Final assembly of any part gets torqued and striped. Full hardware inspection before closing anything and for final.
There are some parts that went on and off a hundred times (for me), why waste the nyloc.
I also used the safety pin style cotters for anything castellated that was temporary assembly.
Do what works for you but don't re-use nyloc hardware.