A: 15 years B: 20 years C: 25 years D: 30 years E: 40 years F: 50 years G: other
I’m almost afraid to answer this question.
The rock from the 60s and 70s got ubiquitously considered classic rock by the early 90s, but I wouldn’t classify anything beyond the early 80s as “classic”. I think that the genre may expand with time, but the 60s and 70s were the true origins of rock. The music past that is definitely not new, but not “classic”.
I guess that makes my answer G.
Edit: From a marketing perspective, I’m about to cringe hard, music up to the mid-90s is considered classic rock. To me that seems like it’s just an easy way to keep “classic rock” more entertaining and nostalgic for the older markets, and more relevant for the younger ones.
I hear bands like Linkin Park referred to as classic rock quite a bit and that’s early 2000’s. I cringe every time someone says it.
The thing is is that they’re not quite wrong.
It’s not quite right, but it will only become more true.
This is a great point that it’s more of a era or genera than a designator to be applied as the work ages. You have Rockabilly, Classic Rock, Grunge Rock, etc.
One of the things that makes music slightly different than durable goods, although I would have a hard time calling anything from the 90’s “vintage,” but it’s getting close to that age.
A big factor I feel is the artists themselves touring.
If the band has a hiatus, gets back together for a last tour, they’re probably classic rock. If the band has a dead member and isn’t replacing them, they’re probably classic rock.
It’s sad that Sublime, Alice in Chains, Linkin Park, and Soundgarden are all in this classic-rock-to-be state only because each band had so much life left in them. And well…
Now they’re probably classic rock.
“Classic” is never an indicator of age, regardless of what type of media or whatever you’re talking about. It basically just means that it is a great example of that category of thing and what makes that category unique.
If it was ever popular and not a current song in the genre of rock, it’s a classic rock song. At least seemingly according to the radio industry.