My mum is still using her iPhone 4 bought in 2010. She refuses to buy another phone She did get an S3 but after a few days she stopped using it and went back to her trusty iPhone. The S3 just sits there unused.
My hubby still uses his 4s and refuses to update. He likes the size, uses it for voice and text only and sees no reason to buy another when this one works perfectly fine. In addition I hung onto my 4s as a replacement for him or a backup in case I ever need it myself. Both phones work still work great. Hubby is not into tech anything so that should explain it.
My wife still uses her iPhone 4. Her first and only smartphone to date. She's not really a tech lover like me, but she does admit that one day it will need to be replaced.