If I recall correctly, once it happened after I changed from live to buying mode - but that was actually not the game crashing, it just froze.
It actually crashed 3 times, once was after I had set a sim to do a number of things (eating, going to the bathroom, sleeping or something like that) and another time I think it happened while one of my sism was writing and the other was fishing (but that probably doesn't have anything to do with anything
), and all the times it happened about 5 or less since I had started playing with the family.
As for game settings I have it as 1024x768, graphically it's mostly set as average, I have aging off, story progression on and I have no other mods installed. I'm not sure if that's enought but I can check the whole settings if necessary.