a co-worker asked me a very good question at work today. What defines classic rock? Is it based on age where once rock reaches a certain age it becomes "classic rock?" If so does that mean when somebody listens to a "classic rock" station in, say, 20yrs they will play rock like mid 90's- 2020? or is rock more of a set genera that has been defined by rock of a certain sound made in late 60's- early 80's where the time to add to the genera has ended or can be added to only if the music has certain qualities? if this second definition is closer to true what is it that makes this rock from the 60's-80's , in fact, "classic rock." Surely this catergory we know as classic rock doesn't encompass all the rock, so what's the difference b/w the 60's-80's rock that is in the "classic rock catergory and the 60's-80's rock that isn't?