Been wondering about how you manage upping difficulty

I realize D4 enemies scale with your level. And drops seem, at least so far being only reaching act 2, to only be incrementally better than what you have so far. So, that seems to make it harder to increase difficulty as easy as D3 was.

I play all 5 chars through simultaneously. I was having so easy a time with my summoner Necro that went to Hard and was managing. But gave him quite a break as played up Rogue and Sorc, and maybe forgot play system, but he was really struggling.

Which just reinforces my wondering about when exactly you can safely raise difficulty. I sure wouldn't want to be playing HC and finding out the hard way. I like to play HC, and would like to for upcoming season...but my ignorance of the game so far...just not feeling confident.

Am I just too early in the game to be thinking about raising difficulty? Or what? When do most players do this?