How To Install Custom Content?
The Sims 4
Custom Content and Mods (Install/Remove/Organize/Fix)
http://simsvip.com/2014/08/22/how-to-install-custom-content-in-the-sims-4/
https://www.carls-sims-4-guide.com/forum/index.php?topic=23495.msg410220#msg410220
The Sims 3
TS3 Custom Content (Basics)
https://steamcommunity.com/sharedfiles/filedetails/?id=454209314
http://modthesims.info/wiki.php?title=Game_Help:TS3_CC_Basics
Optimization Sims 4
http://forums.thesims.com/en_US/discussion/816399/performance-boost-guide
Optimization Sims 3
General Errors FAQ
https://www.nraas.net/community/General-Errors-FAQ
Tips for better game performance
https://www.nraas.net/community/TIPS-FOR-BETTER-GAME-PERFORMANCE
Performance & Bug Fix Guide
https://steamcommunity.com/sharedfiles/filedetails/?id=1131162350
Comprehensive Guide to The Sims 3: Performance and Custom Content
https://www.reddit.com/r/thesims/comments/c9agh2/comprehensive_guide_to_the_sims_3_performance_and/
World Fixes
http://modthesims.info/m/1515002
Where can i download mods 18+ for Sims 4/Sims 3?