According to Apple's privacy page[0]: > Siri and Dictation do not associate this information with your Apple ID, but rather with your device through a random i

According to Apple's privacy page[0]: > Siri and Dictation do not associate this information with your Apple ID, but rather with your device through a random identifier. Apple Watch uses the Siri identifier from your iPhone. You can reset that identifier at any time by turning Siri and Dictation off and back on, effectively restarting your relationship with Siri and Dictation. So it looks like it keeps the same ID until you turn Siri off; if you turn Siri back on, you'll have a new ID. [0] https://www.apple.com/privacy/approach-to-privacy/ https://www.apple.com/privacy/approach-to-privacy/