Each time you want to expand you're going to have to increase your CityVille population first. And once you get into the higher levels, space becomes a crucial issue. You've completed dozens of quests and that means you've added dozens of new businesses, houses, community buildings and attractions. Where will you get the space to add more houses so you can increase your CityVille population so you can expand your city?!
This issue really comes into play once you hit the higher levels. In the beginning, you don't have very many coins to spare so you buy inexpensive housing whenever you're required to increase your population. But all of those little, inexpensive houses don't yield much rent and it takes a lot of energy to keep up with collections. Not to mention the fact that they're taking up a lot of valuable Real Estate in your city.
Just like any real city, at some point a decision has to be made and some of that low-income housing has to be replaced with shiny, new high-rises that will allow population growth and a higher return on investment. Yes. You're the mayor of CityVille and you have to run it just like a real city!
Some of the smaller homes, like the Cozy Cottage, the Country Home and the Family Townhouse only allow 30 to 50 people and yield only a minimal amount of coins. Yet you probably have entire blocks of your city filled with this type of housing because it was cheap and required little energy to build.
Well, you're in the big leagues now. It's time to replace those little, single-family units with some modern apartment buildings and private estates that will allow a lot more people to move into your city.
Before you just start deleting houses, though, you'll need to remember one thing: Deleting a house also deletes that number from your population. So, if you're trying to increase your CityVille population by 400 people and you want to delete 10 Cozy Cottages, you're now going to have to increase your population by 520.
Is it really worth it? Well, it depends on how badly you need the space. But look at it this way: Those 12 Cozy Cottages are taking up an entire expansion area and they net a total of 14,400 coins a day - IF you can spare all of that energy to keep them collected and IF you can be online every single hour of the day. Most people don't even collect the rents on these houses because it's just not worth the energy.
On the other hand, you can replace all 12 of those houses - and their populations - with one Atrium Lofts which has a minimum population of 500 and will yield 495 coins per day, without any decorations. Add decorations and that amount will increase. You'll also be more apt to collect this rent because it won't cost you so much in energy. When you increase your CityVille population by replacing houses you'll end up with a lot of additional space - and some spare energy, too.
Source: eZine