It's absolutely up to you how you play your game. I personally couldn't play without mods. I have tried, but there's a million little annoyances and things I want to change, so I have a huge but carefully curated selection of mods I use.
I currently have around 750 actual gameplay mods, as in, files that change how the game works, not just CC. I also have 30-40 GB of normal CC like clothes and hair and furniture. I don't get errors or lag because I'm extremely particular about sorting and updating my mods and checking for compatibility, but it can be a hassle to keep everything updated, and it can also be annoying to have to wait a few days while all the creators update their mods to be compatible with new patches and expansions (however, this wait also often allows EA to fix a few bugs so I was never hit by the tooth bug in Growing Together, for example).
All these mods make the game more enjoyable for me, so I choose to live with the few downsides because the benefits are huge to me. If you don't feel like messing with mods and the unmodded game is plenty of fun for you, just play vanilla. If you want to use just a few mods like MCCC or UI Cheats or some CC like default skins and eyes, go for it. If you want to go crazy and use 750 mods and deal with the consequences, I totally understand :wink:
It's your game and you get to decide how to enjoy it :sunglasses: