Do you use CC (No Mods, but CC)?

I do. I basically download CC every day. I love using it and having something new to dress my sims in.

Isn't Custom Content a mod?

Only have 2 cc packages in my Mods folder. Both made by me. One default baby outfits and one default where I made the crib matrasses whiter. And thats it. Not anything else ;)

For CAS, I use a skin overlay and body hair. Build/buy: 1 set of DIY showers from MTS and some paintings I made.

I generally don't use cc, but I do use a handful of mods (maybe a little more by now).
The only time I use cc is when I work on my story (which I rarely do). I needed white hair for a character and the light grey we have in game isn't white enough. So I do use a few hair recolours then.

My game is completely vanilla and always will be.

I use both but I only use custom content for CAS. I definitely could happily live without the extra clothes and hair that I have in my game but I could never live without custom eyelashes because I really don't like the weird solid default eyelashes that the game has.

As for mods I definitely couldn't play without those. I have mods to remove situation outfits, fix the horrible emotion system, improve personalities and to stop the endless spawning of random townies. I also have a ton of small mods that are just for the purpose of fixing the bugs that EA never fix. I could never enjoy the Sims 4 without these mods, it has way to many horrible design choices.

I cannot imagine my game without it. I use hairs, clothes, makeups, furnishings, eye and skin default replacements as well as terrain default replacement. I played vanilla for years but much prefer mods.

I do use mods, but holding off on content CC (CAS and B/B) until I know the game is done and will no longer be updated.

A few recolours of some dresses in CAS
And maybe a little too much B/B, but not enough clutter and plants ?