With the sheer amount of locations this game offers I find this thread amusing at best. Its completely your choice, don't go back to a location if you're upset by a faster respawn or go back a month or so (game time) later. There are literally tonnes of areas you can go in this game, or work on a settlement or fifteen.

Game engine is broken from what I'm seeing in this regards. I've not had enemies respawn, but, I have seen specific items in the game world and certain safes/doors reset within seconds of leaving the area and coming back. The newest patch worked for me, for an hour and then is started again.

But the game itself keeps on conspiring to send near -- or often directly to -- locations that have already been "Cleared". For example, I've spent most of 200+ hours working on establishing, building up, and defending settlements. Part of that involves establishing Supply routes. It is literally IMPOSSIBLE to create any route that does not pass near a map location (re)populated by baddies that think provisioners and their pack brahmas were meant for Target Practice. Then too, if a player uses fast travel to take shortcuts to current destinations -- which is what fast travel was designed for, to be used -- the method is to use a known location (Cleared) as a stepping stone to the new destination. But if a Cleared location has repopulated, that can often result in literally jumping into a firefight -- with foes that had theoretically been killed off.

As I have already said, why even bother to label any location as "Cleared"? It should instead be labeled "Known".