All the major stars of the early 1990s had long hair, and rocker Lenny Kravitz wore his longer than most. Perhaps he was tired of people saying he looked like Jimi Hendrix, and so he went for a longer style to differentiate his appearance.
At their longest, Kravitz's dreadlocks came all the way down to his waist. We suspect that they ultimately became impractical, which is why he has a much shorter style now. He still looks cool, though, no matter what his hair's doing.