November 2014 - last edited November 2017
As time goes by, more and more mods and custom content are released and it's totally ok to use them. EA does support their usage in Sims 4 although you'll still be using at your own risk.
A mod is something that changes the game code and because of this, each and every mod needs to be checked with every new patch or they can cause issues. Custom content such as clothing and hair can also become obsolete but not as often.
Because of this, it's very important that you
Please do NOT report anything before you have done this.
The following bugs are already known to be caused by bugs:
Here's a list for patch 03/26: Custom Content - Compilation of Broken CC/Mods for Patch 188.8.131.520
List for broken mods for gender/dine out patch: Broken/Updated Mods (not CC), June 2 patch + Dine Out GP
List of broken mods for City Living Patch Broken/Updated Mods, OCT. 27/16 + CL
List of broken mods for Cats & Dogs Patch: Borken/Updated Mods Cats & Dogs, Nov 2017
I'm currently very picky about mods and cc as a lot of issues are related to them. I'm not blaming everything on mods, I just wanna make sure it's not that.
It seems that there's issues that stay even if you remove your mods and there's enough game issues the devs need sorting out without having to waste time on cc ones.