When you rent from a company with properties in different price ranges, you have more options both now and in the future. As a tenant if you get a better paying job or promotion, you might wish to move to a larger home at a higher rent. Once you fulfill your lease you can get on a waiting list for a different property. The opposite can be true as well, if you have children who have moved out and wish to find a smaller property to rent, you can get on a waiting list for a property at a lesser rent.
This enables you to have more options in a timely manner.