I have played my sim family for ten years and I hate moving to new worlds when I have to build and decorate for hours and hours. I only move when saves either become corrupted or too big. I like big worlds, though, with lots to explore. Storybrook County is a nice world with a small town and city. The save got too big after 3-4 years of playing so now I have moved to Salmon Woods, that is a bit smaller.
I like to send my sims on holidays to other worlds sometimes, using the NRaas Traveler mod. But travelling is risky, so recently I have started new "holiday saves" and placed my sims in those worlds instead.
Sims 3 should have been a 64-bit game so it could have used more RAM. Then really big worlds (and saves) would have been possible.