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Vodafone Finds Brits Keep Mobile Phones for 4 Years Instead of 2
(www.ispreview.co.uk)
This is a most excellent place for technology news and articles.
As far as I know, until recently no android phone manufacturer except Google provided updates to their phones past 1-2 years. So while it’s been possible, I have never recommended keeping an android phone past 2 years.
See https://www.androidauthority.com/phone-update-policies-1658633/ for some background info if you think it’s just anecdotes