An architect discusses historic preservation and ends with two paragraphs on the changes that neighborhoods experience:

Yet embracing historic preservation too fervently and dogmatically can be problematic. Not all old buildings in historic neighborhoods are salvagable. Some are functionally, technically and architecturally beyond redemption. And over time entire neighborhoods change in ways that necessitate appropriate physical changes. For example, homes constructed 50 or more years ago, perhaps unrealistically small and impractical by today’s standards, may need enlarging, upgrading of windows and exterior materials, and new environmental systems.

Furthermore, insisting that all new buildings look like old buildings in a neighborhood is an overly restrictive policy. Good architects can design modern buildings that, without being historic replicants, aesthetically harmonize with historic buildings. Indeed, mindlessly creating architectural clones denies the natural historic evolution of neighborhoods, towns and cities, where community fabric is collectively enriched over time as human needs and desires, available technologies and aesthetic styles play out.

Perhaps the trick is ensuring that this “natural historic evolution” happens more smoothly and both sides, those who want to preserve some of the older buildings and those who want to build new structures, feel like they are getting something out of the deal. I wonder: are there neighborhoods that have successfully done this?

Additionally, what is the time frame for this natural change? A few decades? Fifty years? I would suspect this would depend on the neighborhood, particularly if the older neighborhood had buildings people wanted to save. I’ll be very curious to see what happens to suburban neighborhoods. Particularly for post-World War II suburbs, how much will people want to save? If McMansions are lower quality construction, as critics charge, will they last long enough for people to want to save them?