Now that I have almost completed the first round of Sunset Valley, I have learned a couple of things about Story Progression's inner workings and the game itself that I wish I had known when first started out.
1) I wish I had known about the Face One Virus. When I first started playing, I didn't know all of the townies were generated with the same face. I thought The Sims 3 behaved more like The Sims 2 which generated the townies from a set of templates. For more details about the Face One Virus, see my legacy blog entry where I explain it in more detail. Since I initially allowed the homeless to move in, I have a lot of townies running around with the same face. I am seriously considering annihilating them with Master Controller so that their genetics don't overrun the town.
You can prevent this situation by installing Twallan's Register Mod and configuring Story Progression to generate townies from your Sim bin. See Twallan's FAQ for more details about managing immigration.
2) I wish I had known I could limit the number of romantic interests a Sim can have. This didn't really become a problem until Generations. With the introduction of the Romantic Reputation system, Sims with multiple love interests have a difficult time maintaining a steady relationship. This is a big part of the reason why you see my Sims break up so often. Twallan's Story Progression Mod has a setting under the "Flirt" menu that specifies the number of romantic interests a Sim can have at a time. By default, it is set to zero, which means there is no limit to the number of romantic interests a Sim can have. I have now changed this setting to 1. I am hoping that will reduce the volatility in the Sims' relationships. I don't think it will help the current young adult/adult generation much, but I am hoping it will help the future generations.
3) I wish I had known the EA team was going to release so many darned neighborhoods. Ok, I put this one in for the lols, but seriously they have already released eleven neighborhoods and there is at least one more on the way (Moonlight Falls). Sheesh! It's going to be 2050 before I finish this thing. Hopefully, I live that long.