Does DeviceID via the webAPI ever change? If so, under what circumstances?

[allofus_project]

Working on a project with about 50K fitbit devices (AllofUs). DeviceID is part of the data from each user, but some users have many deviceID values over time, so I'm wondering if a factory reset, or other user-initiated behavior can change the DeviceID.

Typical device upgrade purchases are expected over time, and I see that behavior, but if someone has the same device type (e.g. a Fitbit Charge 5), but also has many deviceIDs (in rare instances, 10+ different IDs), it has me wondering what causes this. Are these actually new devices, or has the ID just changed for some other documented reason?

Thanks ahead.

[DorisFitbit]

Hi @allofus_project 

Thank you for reaching out. 

The Device ID is created every time a device is connected or paired to a user's account. This explains why you might see multiple IDs for the same device over time.

For a permanent ID that never changes, you should check the MAC ID. It stays the same even if you factory reset the device. Just keep in mind, we can only get the MAC ID for Fitbit devices (like a Charge 5), not for a Google Pixel Watch. 

Hope it helps! Please let me know if you have any further questions.