I did my thesis on this back in 2018, around 566k fingerprints, mostly phones. Can confirm they change a lot. Almost 10% of returning devices had a new one within a day. iPhones were the worst to track, only a third of them were unique at all.

We wanted to use it so people don't have to log in, and dropped it. Good enough for ads, not for anything where you need to be sure it's the same person.

Data is old now though: https://virpo.sk/browser-fingerprinting-hraska-diploma-thesi...