Miners can leave and rejoin the network at will. But they will need to retain the UTXO set as long as they intend to be there, and as long as they are going to continue to try to mine valid blocks. This is because they need the UTXO set in order to make certain that the transactions in their block are valid, and that it won't be rejected by the rest of the network.
Miners can leave and rejoin the network at will. But they will need to retain the UTXO set as long as they intend to be there, and as long as they are going to continue to try to mine valid blocks. This is because they need the UTXO set in order to make certain that the transactions in their block are valid, and that it won't be rejected by the rest of the network.