In real life, buildings come down, new ones go up. Towns expand, become cities. Towns lose population, become abandoned. Trees grow, trees die. Climate shifts, deserts grow or shrink. So much can happen. I thought about this when I saw this today:
The centre of this road where the brown wall is had a lot of cherry trees lining a central walkway. Now they’re gone. Every tree is gone. Why? Well, these trees are called Somei Yoshino, and they have a 70 to 80 year lifespan. Last time I saw them, several of them were dead. They were all likely planted at the same time around 70 or 80 years ago. They were all dying. It looks like they’re going to plant new ones and probably do some repairs.
When developing a fictional world, it’s important to understand that changes happen. If a book happens over a span of years, or if a series of books happen over a span of decades or even centuries, things must change. It’s highly unlikely that the status quo will be maintained. If you have a town, make sure that the population changes over time, new buildings are built, old buildings go into disrepair and may be demolished, new neighbourhoods pop up, and people change. Even important landmarks may be destroyed. Don’t be afraid to do that.
A dynamic and changing world is much more interesting. It can be challenging to keep track of the changes, but it contributes to the realism of your world.