I assume that the TTL of the money would reset once it has changed hands

In theory you spending it would reset the expiration date.

If you know your money will expire you will spend it, thus stimulating the economy. We also can’t have the dirty proles save their way to a higher social class.

I think Japan did try this, as they really wanted people to spe d, vs save.

The government could issue money that can be tied to a specific purpose (allowed to be spent with specific merchants or establishments) and have a time limit. Think of the COVID-19 assistance that was given to people. If — instead of just transferring normal money into people’s accounts that allowed people to do whatever they wanted with it whenever they wanted and wherever they wanted - the government could force recipients to spend it across certain things and not others, and gave a deadline to move the money around, would that be something that’s in the best interests of the receiver? By expiring money or by applying negative interest rates, the government can offload its burden on to the people who hold and have to use this money.

That's a question you should ask China. If it's possible, you can bet it's going to happen sooner or later. https://coinpri.com/news/cryptocurrency/the-chinese-cbdc-wil...

Many ideas aren't new, but that doesn't mean they're government policy.

He merely suggested a small fee though. 5.1% per year and only on cash, not some CDBC with privacy concerns. If you keep your money on savings accounts you wouldn't pay anything. If the economy is growing you would get paid interest. If the economy is declining you might pay negative interest.

This is different from a coupon that expires instantly. That is a terrible idea. Don't do this.

Also, the idea of demurrage currencies is to replace the devaluation via inflation with a nominal fee so it is possible that in countries with high inflation rates, the new currency would end up losing less value over time simply because it maintains price stability easily.

Edit: btw. His theory is dated in the sense that Keynes and Dieter Suhr have an updated interpretation. With a hint of Fisher Black you are going to get one of the most interesting economic theories that can explain most of the suffering in the world based on very few assumptions. The money and land reform policy proposals still remain relevant today.

It can also be programmed with an expiration date to encourage you to spend it to stimulate the economy instead of saving it.

It is called EBT and it already exists and the thing is people demand this for welfare payments all the time.

I don't think the government is trying to protect drug dealers or tax evaders from themselves. You intentionally chose a weak argument to fight against.