Question about saves?

I have deleted multiple destinations world, university world and have no issue with my saves even after I went back to the said world, but if you delete them, every time you go back to this world, it will be as if you haven't go there, all the townies are refreshed (all sims are still in university and none have graduated, tombs are refreshed, etc).

But don't delete oasis landing nhd as that will mess up Emit Relevart npc.