I back up my saves and tray folders frequently -- once a week minimum, plus before every patch. That way if I do run into an issue I can restore my game from the backup and hopefully don't lose much gameplay or my Sims/builds.
Some people suggest using Save As... instead of Save and choosing a new save name, or deleting the localthumbcache.package file before playing. I've only had one issue with a corrupted save, and it wasn't an error code that showed up but rather festivals were no longer spawning (I'd get the notification, but when my Sim went there no festival objects or events showed up. I don't think I've had a single error code event in my game.)
