What Happens to a Transaction in the Mempool If It Is Never Confirmed?

If a transaction remains unconfirmed in the mempool for a very long period, it will eventually be dropped by most nodes. Each node maintains its own mempool, and transactions have an expiration time, often around a few days to a week, to prevent the mempool from growing indefinitely.

The sender may then attempt to rebroadcast the transaction or create a new one with a higher fee (RBF) to ensure confirmation.