My towns would've died off or turned into dysfunctional nightmares without Mods if that save didn't end up corrupted by a social worker taking a child away or by the EA bugfest glitching things out and starting pregnancies in wrong ages like it did for me a few times in unmodded games.
I've got my game loaded with over 700 Mods including the 113 Nraas Mod files to fix many of the issues and I'm now able to play a town for multiple generations without it dying off because of the EA bugfest messing things up and my sims will get married or have babies though I have to play rotationally like TS2 to get that town to progress and grow over time.I also won't face routing issues from a town being overpopulated and overcrowded too suddenly as I have control over the population like Sims 2.