This is a good question. I play a rotation of different sims with different personalities. In other versions of the game, I would play a bunch of different households but never really go back to the older houses when I started a new one. Now, I go between these different households that all interact with each other. In that way, I don't get too bored. That also means that I experience a lot of different settings and houses.
I try to match each sim with a household to suit their personality/personalities and budget. I do have sims with different social standings in the community. I tend to find that the style of the house influences the sim a bit but then I also try to make sure that the decor and any renovations suit a particular sim as well. All of my sims have distinctive personalities and interests so I generally know where I am going when I move a sim or adapt their homes.
Just recently, I was thinking about how several of my households really don't need any more "stuff". Their homes and furnishings really do work for them perfectly; they have their own senses of style and the spaces just feel great. It's a great question to ask how I know that they've reached that point. It's also the case that dynamics may change as my town gets fuller and there are less new options to move to. Honestly, at that point, some sims will need to become townies or to "move out of town" permanently.
So, how do I know that a home is right for a specific sim and that their furnishings suit them? Like I said, I guess I really develop their personalities so I know what I am looking for. All of them are a bit different in terms of what they want. For a moving sim, I will look at the available lots in their budget or the lots that are realistic for them. If it's a middle class sim, I might consider doing free real estate to get them a house worth 10k simoleons more than they have and I'll say that they got a mortgage. I won't move them into the biggest mansion though.
What is a specific sim's style and motivations? I guess that I try to figure out which world they might want to live in first. Do they want the relaxed vibe and hot temps of Oasis Springs? Do they want to be in Windenburg? (Most who live in Windenburg are either born there or marry someone there). Are they looking for a classic suburb like Willow Creek (or eventually Newcrest where I have a few lots left)? Do they want the excitement of San Myshuno? Many do but now there are only a few more affordable apartments for those who aren't very wealthy to choose from.
Sometimes I do renovate a lot to offer more space and to suit certain sims. Those end up being some of my favorite lots because they do feel very customized. I've turned the penthouse in the Arts Quarter into a two storey aerial loft that is spacious, elegant and really offers a lot. That might be my favorite renovation now. The penthouse fits the family perfectly with the right amount of space. The style is a mix of modern, elegant and romantic with a pool in a bright sunroom and a new art studio that I added. Other than adding more art, it doesn't need any further objects or anything significant to really suit them. It feels like something that would be very expensive in real life metropolises because of the space, features and design.
Not every house is as swanky as that one but I know that the sims feel at home because of the way that they interact with their furnishings and with the spaces that they live in. It might be a simpler house full of rambunctious kids and a fun yard but if that makes those family-oriented and more modest sims happy? It works. I guess that I get to play around with a lot of different styles in the process. Every home feels a bit different from the others.
