Destination Tags (Critical)

Exchanges require destination tags to credit deposits — sending without tag means lost funds or lengthy recovery
Destination tag is a number (not text) attached to a transaction — identifies which user's account to credit
Always verify tag before sending to exchange — wrong tag sends funds to wrong user
Self-custody wallets don't need destination tags — only exchanges and shared wallets use them
If tag is forgotten, contact exchange support immediately — recovery is possible but slow

Account Reserve

XRP accounts require 10 XRP base reserve to exist — this is locked and not spendable
Each "object" (trust lines, offers, escrows) adds 2 XRP owner reserve — more features = more locked XRP
Cannot send entire balance — must leave reserve amount or transaction fails
Reserve amounts can change via network amendments — currently 10 + 2 per object
Deleting account recovers most reserve minus 2 XRP fee — requires no objects and destination tag

XRP transactions settle in 3-5 seconds — much faster than Bitcoin/Ethereum
Transaction cost is ~0.00001 XRP (fractions of a cent) — burned, not paid to validators
No mempool or pending state — transactions either succeed immediately or fail
Sequence number per account like Ethereum nonce — transactions must be sequential