I think it depends on what you’re writing about. Violence, sexual assault, or just sex? Sex for me can’t get too explicit - but violence certainly can, and especially sexual assault. Most of the time it really isn’t necessary to write an explicit sexual assault scene.
With Erotica, explicit sex scenes are kind of a must.
With Horror and Dark Fantasy, explicit violence in different degrees are more or less always a must. And by describing how a head is cut off, how hard it is to cut through the windpipes and bones and all, that can get too explicit, IMO. But sometimes it’s necessary to go all the way. You just gotta know when.
This was a ramble. Sorry about that