In order to be able to claim that you got the full experience of given decade, how many years prior to the decade would you need to have been born.

It's kind of an interesting question in general. A lot of current "hipster" culture is based on a lot of bands/styles of the 90s. However, I know a few hipster-ish people that claim to be 90s kids that were born around 1989. I say that's bullshit. I was born in 1987, and while I feel as though I remember most of the 90s, I remember very little about the early 90s. Folks who were born after that are really starting to reach the point where they must not remember jack shit about the entire first half of the decade.

I'd also say that if you were born 2 or 3 years into a decade, you're kind of a tweener. You get to pick which decade to associate with!