@mollyf3 Repairing should not have any effect on any of your existing content. Saves, saved households and builds, and other user content are stored in Documents > Electronic Arts > The Sims 4, a folder Origin doesn't touch during a repair or any other time. Still, it's a good idea to back up this folder periodically anyway because you never know when you'll have a computer problem. Some of us keep whole copies of the folder; others just preserve what we see as the most critical files.
Your Gallery data—uploaded content, download count, that sort of thing—is stored on EA servers, not your computer.
