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.

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...

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

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