Address reuse

In plain words

Every payment to an address is public forever. Use one address twice and everything sent there gets linked: income added up, senders connected, spending traced onward. Wallets solved this long ago — they make a fresh address for every payment, all backed by the same seed words. So the rule is easy: hand out a new address each time, and never post one anywhere permanent unless you want a public tip jar.

Why it matters

• The single cheapest privacy win in Bitcoin — your wallet already does it.
• Reuse leaks about the people who pay you too, not just you.
• Chain analysis starts from exactly these links.

Not to be confused with

• "New address = new wallet" — fresh addresses all belong to the same seed; there's nothing new to back up.

Go deeper

• Chain analysis
• Address types
• Keys & addresses