The BIP-444 soft fork proposal is designed as a temporary one-year measure to restrict arbitrary data in Bitcoin transactions, aiming to address legal and spam concerns related to on-chain data. This means the soft fork chain created by BIP-444 could be the "lightest" (i.e., the active or preferred chain adopting these rules) for about one year, as the proposal itself explicitly states a one-year duration to give the community time to evaluate and develop longer-term solutions. However, the actual duration in practice could vary significantly depending on miner and node adoption, community consensus, and potential support or opposition from economic actors. Since adoption of Bitcoin Core v30 (which relates to these changes) is still relatively low, the real network effect may take longer to fully manifest or might face divisions leading to fork scenarios. In summary: Intended minimum duration: approximately one year according to BIP-444’s stated temporary soft fork period. Actual effective duration: depends on consensus dynamics, miner and node support, and network upgrades; potentially shorter or longer if disagreements cause chain splits or delayed adoption. No fixed block number or time beyond that one-year proposal is currently defined, so careful monitoring of miner signaling and node adoption rates will be crucial to estimate how long the BIP-444 chain remains the main (lightest) chain