You can implement this already, but only for ~1 year expirations.

IF <normal script> ELSE <1 year> CHECKSEQUENCEVERIFY ENDIF

Perhaps it would make sense to propose a flag extending the range of relative
lock-times so you can do several years?

Luke


On Monday 11 December 2017 5:30:37 PM Teweldemedhin Aberra via bitcoin-dev
wrote:
> It is estimated that about 4 million of the about 16.4 Bitcoins ever mined
> are lost forever because no one knows the private keys of some Bitcoin
> addresses. This effectively mean there are actually only 14.4 million
> Bitcoins in circulation even though 16.4 million are mined. There is no way
> of eliminating the human errors that cause these losses of Bitcoin from
> circulation, while the number of Bitcoin that will ever be mined is capped
> at 21 million. This means the total number of Bitcoins that are in
> circulation will eventually become zero, bringing the network to an end.
>
> The solution this BIP proposes is to implementing a dead man's switch to
> Bitcoin addresses. The dead man's switch causes the Bitcoins assigned to
> dormant addresses to automatically expire. A Bitcoin address is deemed
> dormant if it is not used in transactions for some fixed length of time,
> say ten years.
>
> The calculation of the miner's reward should take into account the Bitcoins
> that has expired. This means there is a possibility that miner's reward can
> increase if sufficient number of Bitcoins expire.
>
> Ref:
>
> http://fortune.com/2017/11/25/lost-bitcoins/
>
>
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