How Can a User Estimate the Optimal Fee for Their Transaction?
A user can estimate the optimal fee by observing the current state of the mempool and the fee rates of recently confirmed transactions. Various fee estimation tools and wallet software analyze the data of unconfirmed transactions and the fee rates of the last few blocks.
These tools provide a recommended fee rate (e.g. sat/vbyte) to achieve confirmation within a desired time frame (e.g. next block, within six blocks). The optimal fee is the lowest amount that is competitive enough to be included by a profit-maximizing miner in a timely manner.