For a long time I would upgrade every 1 1/2 - 2 years but I've had my i7 920 for 4 years in January and still find no fault with it.
I can OC it to 3.6ghz without hitting the voltages and I've never had any stability issues at all in those four years.
The newest game I've played is Skyrim with no issues. My everyday game is LOTRO and it isn't very demanding so no problems there at all.
I've thought about upgrading just for the fun of it but the 920 still purrs like a kitten... So am I just getting old or is the ole 920 just that good?
I'm going to say it's that good.
Dang... I need to change my Depends...