Buildings should represent the correct mix of uses that are needed for the community to function, which include: residential, commercial, and civic.
Residential: Single Family, Multi-Family / Townhouses, Apartments & Condos
Commercial: Retail, Offices, Mixed-Use
Commercial Characteristics
Closer to the road
Signage
Ramps
Parking instead of a yard
Civic: Schools, Libraries, Town Hall, Churches
Buildings can change their use over time. Residences along a busy street might develop commercial characteristics, such as an open floor plan, a unified façade, high ceilings, large windows, etc., which work better for commercial purposes.
At each level of community, there is a physical and symbolic center that consists of civic uses. It is the heart of the community. It makes decisions for the community, and it coordinates with the other levels. As the town grows, its population can support new uses, such as a university, hospital, and stadium.
To support shared services within the listed walk times, the density requires at least 4 du/acre. At 10+ du/acre (row houses), the 100,000-person level that constitutes a county is a city, and it only takes 15 minutes to reach the center. Dense cities have everything within walking distance, but it's important that local services are provided at the block level so people feel connected to them.