2014 is a nice machine I truly don't understand why people hate it so much.
Back to the topic. My 2009 MM ran for 6 years before I sold it for newer model, it kept running for at least another year with his new owner if I recall right, it had ElCap on it. My last iMac was also from 2009, and ran for 5 years until he died. My next *Mac (I hope for new MM, still!) will serve me as workstation for 3 years before turning into HTPC until end of life.
These machines last long, often more then they should.
Back to the topic. My 2009 MM ran for 6 years before I sold it for newer model, it kept running for at least another year with his new owner if I recall right, it had ElCap on it. My last iMac was also from 2009, and ran for 5 years until he died. My next *Mac (I hope for new MM, still!) will serve me as workstation for 3 years before turning into HTPC until end of life.
These machines last long, often more then they should.