[CydeWeys]

The claim I was responding to was that people should be able to do "whatever they want" with their properties, which encompasses a lot more than just leaving them vacant.

But to answer your specific question, the most obvious negative externality is increased rents for other people, because an apartment that could be being rented out (increasing supply) isn't being rented out.

Having lots of vacant residences also potentially increases crime, is bad for neighborhood maintenance (we have a huge problem here in NYC of sidewalks not being shoveled in front of vacant properties when it snows), it gives pests a potential home, and increases the potential to damage surrounding residences. Vacant residences are more likely to fall under disrepair and then catch on fire or start leaks, which can damage nearby or underneath residences. If you're touching one then it's bad for your heating/AC bills, because your heat/cold is sapping through the walls into the un-conditioned apartment. Even just simple things like having fewer eyes to watch out for crime and call the police if a burglar or robber is spotted.

There's a huge host of problems associated with having long-term vacant residences in your neighborhood.

[bradleybuda]

Are you currently selling your unused possessions on Craigslist? That camping gear or extra set of kitchenware? By not selling your things, you are making those things more expensive for everyone else. Therefore, you are creating a negative externality by not selling your things, and storing unused property in your garage and basement should be illegal.

What you are describing is not an “externality” in the way that economists use that term.

[Dylan16807]

Land in a developed area is in very limited supply, it's necessary to make the economy function, and most of the owners are speculating on the price going up. Kitchenware doesn't work that way. Almost nothing else works that way.

Owning central land and not using it means that millions of people have to go further to get to their destinations. It also means that construction effort and money is going into a black hole and not turning into supply. Enough of this together makes a powerful negative externality.

[dehrmann]

> Land in a developed area is in very limited supply

Because of high rises and land reclamation, this is a lot less true than you'd think.

[Dylan16807]

The zoning has to allow for building up before that counts.

[cycrutchfield]

And thus you have arrived at the central issue here.

[xenadu02]

People need homes to live. Shelter is essential in the way very few things are.

[cycrutchfield]

How about you start paying fines for all that unused food in your pantry?

[baroffoos]

If there was some financial incentive to buy food and leave it to rot and this was causing a food shortage then yes, that is a sound idea.

[alanlamm]

Yes, or even better, for all that surplus lard on your body!

[brandonmenc]

> Are you currently selling your unused possessions on Craigslist? That camping gear or extra set of kitchenware?

Can you create new land?

No. They are completely different things.

[cycrutchfield]

You can create a lot of housing out of a fixed amount of land. All you have to do is allow developers to build up.

[spoondan]

The ability to apply the same argument to another situation has no probative value. Any policy has its pros and cons. One can support vacancy taxes/fines without supporting other taxes on unused possessions.