1. Does Apartment Life have the limited installed option in it? You can only install it 3 times and that's it I have heard rumored. This is the deal buster. I have had my ipod for exactly a year and will have to gone through all 7 installs with it.

Now if it is unlimited installs,

2. What are these social groups? Jocks, leather heads... How do you become one? Is it automatic? How many are there?

3. DO you have to play in Bellacove to use apartments? I like building my own neighbor from scratch so to speak.

4.Would you buy it now knowing what you have learned about the game now?

Answer to #3 No you can build your own apartment complex anywhere. what confused me in the beginning is that you have to build the complex then use a code to convert it to an apartment. I have built several apartment complex's in my own neighborhood.
4. I wanted the expansion pack for the toddler interactions and playground toys. It is cool to have apartments but for me its like building another lot. The apartments have the university dorm feel for me. Even to build after the fact you have to use a cheat code because the game will not allow you to delete and build a wall if there is a sim living there.

i want to know about the social group question too, i want to be in a social group, but have no clue how...

2. I've yet to find any use for the social groups. Has anyone found them useful?

3. You can have apartments anywhere, except in university neighborhoods. There's a hack to put apartment in university.

4. Apartments reduce cash flow problems. You can rent a spacious apartment for a fraction of the cost of buying a house. In less than two weeks, you should have enough money to move out and afford a lot and all the better items you want with it.

The Social Circles are a nice Flavor The makers added to diversify BellaDona Cove. Also you'll find certain Social Groups belong in certain areas of the neighborhood. Like, the GearHeads you can find in the slums more likey and the artsy Uppidty Sims in the more Expensive Zoned Areas of the Neighborhood . Also Each Social Group has their Own Gesture. Jocks like the Hi-Five interaction, GearHeads the Tough Handshake and so on. By Properly interacting with the Social Group with the correct "Gesture" you score higher points. Some times i get 25 or 30 points off the bat of meeting a new Sim who belongs to a social group and performing the right social Gesture. Like Giving the Jock a Hi Five. Quicker way to build friends and high Daily Relationship Scores. You can make friends with them fast this way and by telling a story that fits their Social Group makes their Daily Relationship score higher too. I find them useful for networking, and making fast friends. Great for Popularity Sims or Sims with High Friend Job Promotion Requirements.
You can't per say become part of a Social Group, but your Sim can Dress Like a Social Group and try meet and make friends who belong to a certain group. Also doing positive interactions on Community Lots helps raise your Reputation Status Bar. I had a sim with a High Reputation Status Bar and sims would walk up to them in community lots and start talking, doing Social Gestures, offering me jobs and products.
Lastly I have the game and think it adds many things I've wanted for a while. Like Ceilings! Ceiling Fans and Play Ground Equipement. Also the ability to Walk to Work and Walk to School. So if you wanna save some duckets on a car that option is there too, or if your Sim overslept or missed the carpool they can now work. Oh and know this is long but RoomMates in Apartments are kind of cool. If Kept Happy roommates pay their rent on time!