Bitcoin Days Destroyed
Bitcoin Days Destroyed measures transaction volume on the Bitcoin blockchain in terms of how long a quantity of Bitcoin has been held by a certain UTXO/user without being moved. The equation is as follows:
BDD = Bitcoin quantity * days since coins were moved.
For example. If you spend 1BTC that you earned 7 days ago, there would be 7 Bitcoin days destroyed. But if you spent 1BTC that you earned 700 days ago, that would be 700 Bitcoin days destroyed.
The metric is useful in determining how long people hold their Bitcoin.