What should you check particularly carefully before sending bitcoin to another person?

Detailed explanation

An outgoing payment should be signed only after checking the recipient, on-chain or Lightning route, complete address or invoice, amount and fee. With a hardware wallet or external signer, the outputs and amounts actually shown on its independent display are authoritative.

For on-chain payments, check the fee rate as well as the total fee. Wallets may show priorities such as slow, normal or fast, or a confirmation target. These are estimates. The right choice depends on urgency, current mempool conditions, virtual transaction size and personal cost considerations.

An unusually high total fee should be questioned before approval. A very low rate can cause a long unconfirmed wait. Fees can be substantial relative to small payments. A provider's withdrawal fee is not automatically the actual Bitcoin network fee.

Lightning uses different fee and routing mechanisms; on-chain fee rules must not be transferred unchanged. Software can confirm an address's syntactic validity but not that it belongs to the intended recipient. If uncertain, stop before signing and check through a second trusted channel.