Popular cryptocurrencies process many thousands of transactions per hour, and many wallets choose to retain a large fraction of that data. In which case a few y

Popular cryptocurrencies process many thousands of transactions per hour, and many wallets choose to retain a large fraction of that data. In which case a few years of operations easily yields dozens of GB of storage. In theory though, through the magic of Merkle trees, a superlight client could get away with needing only a few KB of storage, accounting for the paths through the Merkle tree that witness its spendable outputs. A discussion about such a setup for Bitcoin can be found for instance at https://bitcointalk.org/index.php?topic=88208.msg1896213#msg1896213 https://bitcointalk.org/index.php?topic=88208.msg1896213#msg... I don't know of any crypto-currencies that have implemented these UTXO commitments that would allow for such wallets though...