when does something become retro?

I hate to think that my own childhood is viewed as being “retro”. Has there really been such a huge jump from 90s music to the present? Or so much so that we need shows that like “so 90s” … Any music that is from the past 10 years really doesn’t seem horribly dated. Ok, play a 1992 Paula Abdul video and I will put it in the retro category – but anything late 90s still seems relatively relevant. By relatively I mean that it is still played on the radio, some of the bands are still together from that time and not everyone has made a huge Britney Spears like turn around.
Then again, being retro seems so cool now. Even Madonna has become a retro version of herself. Everyone seems to be trying to relive the 80s, with our leggings, over the shoulder sweaters, and budding coke addictions.
I don’t know…

Then again, there is the generation difference of viewing what is retro and what isn't. When bellbottoms first came out I thought they were the "new thing". First my mother corrected me and told me about the 70s. Then my grandmother told me about the 70s, and the 40s. She said she wore them both times around but wasn't sure how she felt about them in 1997.
With that as an example, then the permissable cycle of reviving a "retro" trend is about every 20-30 years - so that explains the 80s revival.
But for the sake of my sanity - leave the 90s alone!!!!