It's specific to the mechanism, always. If you modify a revolver it won't do much good to have a list reminding you to verify disconnector operation. It doesn't have one. This is why whole books are written devoted to different firearms models and their variants. They all seem to have unique quirks.
They also are all capable of exhibiting reliability problems. A competent gunsmith can provide a reliability package for most handguns and improve their ease and smoothness of operation. The steps, again, vary with the model. This greatly improves the probability of correct operation, but given that even factory ammo fails from time to time, nothing can absolutely guarantee it,
