Imagine calling a restaurant every day and giving detailed food preferences. Every single call, the person who picks up has never spoken to you before. You have to explain everything from scratch. That is what talking to AI is like. No matter how long your last conversation was, the next one starts from zero.
If an app seems to remember your name or preferences, that is the app doing it, not the AI. Apps like ChatGPT save notes about you behind the scenes and quietly paste them into every new conversation. The AI itself has zero memory. The app is faking it.
This also means anything you shared in a conversation disappears the moment the chat ends. Some apps work around this by asking AI at the end of a conversation "Is there anything from this conversation we should remember?" The app then saves those notes and quietly injects them into future conversations. But that is the app remembering, not AI. AI itself still starts every conversation with zero memory.