Folks, here's what has been working for me as I explore these infuriating error codes.
One - saving. Never ever never ever never save when in university, high school, lovestruck locations. That will corrupt a save file.
Two - when code 0 appears, use Save As. Create new save files and delete the bad ones.
Three - make a routine. For me, I built a house in Oasis because the saves seem to work there. End of the sim day, save. Every sim day so I won't lose much progress just in case. At the end of my playing for a time, I make a Save As file. I have three that I rotate through save1, save2, save3, and overwrite the oldest with Save As. That way, if one goes bad, I have two recent backups.
Four - Save As is your friend. Even in the world screen if all else goes wrong.
Five - I don't know why, but checking neighborhood stories regularly at the mailbox seems to keep things stable. Might be coincidence. Might be like rubbing a rabbit's foot but I do it.