Board Thread:General Discussion/@comment-26288871-20150408124936/@comment-5379325-20150511073300

Freenight wrote: The choice of your screen name is rather ironic.

Anyway, the answer is yes. Most NPCs need only saving(tinkerer, mechanic) or fulfilling their requirements(nurse, dryad) once in that particular world. When they die, they will respawn as long as there are suitable houses. I would like to point out that you do need to fulfill the spawn requirement again if the requirement(s) involve you the player. eg. if the arms dealer died you need to hold a bullet-firing gun/bullets to get him spawn again; 50 silver coins if the merchant died; have a character with 120+hp and merchant for nurse etc

But some NPCs spawn requirement are considered a world property (eg. people you saved or those spawn after x boss is defeated) and will always be fulfilled in that world.