Everyone who cares about their privacy should run a full node. Great article about the options currently in use and development over time.

“Every Bitcoin wallet faces a fundamental technical challenge: how do you discover which transactions belong to your addresses without revealing those addresses to others?

The solution you choose determines your privacy.

Download everything and reveal nothing, or query servers and expose your financial history. There is no middle ground in the protocol design, only different points on the privacy-convenience spectrum.

Bitcoin's blockchain is public. Your addresses don't have to be.

Full Nodes: The Original Standard (2009)

When Satoshi launched Bitcoin in 2009, there was only one way to use it: run a full node. Download the entire blockchain, every transaction ever made. Your node asks for everything, reveals interest in nothing.

How it works: Download every block, validate every transaction, maintain the complete UTXO set (~11 GB). When checking your balance, scan the local database. When broadcasting transactions, relay through the P2P network alongside thousands of others.”