I used to never play rotational, but after I figured out there was no story progression, I had to do something because I was tired of all my sims in town dying of old age, single, and childless. I needed friends/cousins etc. I've turned aging off except for current household so I don't have people randomly dying or aging out of range for friendships etc (until I'm ready for them to). I keep it on for the current household though because the race against the clock (as it were) is one of the few challenges in the game. I don't rotate families on any set schedule, I just rotate whenever I get bored or need to rotate to keep age groups aligned.
1. 9/10 times I begin with one sim. That sim becomes a "legacy" founder and that sim I will use to populate a lot of the world over multiple generations. Over time, I will have to add more sims, but I add them later when I have an idea what the offspring will need for personalities for potential friends and mates. They usually start with an empty lot or bare bones house and I "rags to riches" style game play. When the next generation grows up, I legacy style it, and one will inherit the house and the other siblings move out (if there's multiples). The ones that move out then move onto their own legacy of sorts and again back to the beginning with the whole rags to riches thing.
2. Starting with one and then growing a family. They're all various sizes and I've played with anything up to 8 sims and a variety of pets and non pet households.
3. Depends on my save and my RL. I play other games besides sims too so I will take a break if another game is catching my interest. If I want to play sims and bored with the current save, I have other saves I work on as well. I build. Right now this current save has been worked on since last February with small breaks.
4. I use Newcrest as more of a place to dump a lot of venues. I have restaurants there, church, graveyard, outdoor cinema, shops, cafes. Depending on the save and the story happening in my head is where my sims live. I love Forgotten Hallow and Strangerville though, they are my favourties to look at, but I tend to use Sulani a lot. Lately I've been in Willow Creek the most.
5. The biggest draw back for me is eventually there becomes too many households to keep up with. Right now I'm on Generation 5 and there's 5 groups of families all related. Of those 5 groups, 3 have 2-5 children each and when those kids grow up... I don't know what I'm going to do! :D
6. I guess I prefer families. I just prefer to build them up from nothing. The only times I create entire families in CAS is when I'm making townies to move in for my sims to have friends/mates etc. I also prefer them to be occult too. Aliens are my favourites, but I have soft spots for the others as well. I also love to have chaos in the game. Anything that helps to hinder some of the family members is welcome in my game (murphy beds as an example). I like a little bit of risk and I like the challenges that come with that. When the game stops challenging me is when I usually stop a family or even an entire save.