I've had hair past my shoulderblades since... 1991. I've kept it in a ponytail since '93 or so. In '96 I had a girl clip the stuff on the back of my head under my ears; my reasons were entirely pragmatic as I went everywhere in an open-topped Suzuki samurai I'd modified with SJ-410 hinges so that I could fold the windshield down and by shaving the back I was able to contain most of it in a bandanna. That haircut has been maintained by $70 Aveda ninjas; it's currently clipped by a talented guy named Marty on the Compton/Westchester border. I think I'm one of the few white guys whose hair he cuts. It was the back, I think, that allowed me to maintain it throughout my professional career. One nice thing about being in concert sound is a long ponytail generally means you know what you're doing. Location sound, not so much; another sound mixer buddy of mine has referred to me as "the only pony tail in Los Angeles." Depending on my mood, I refer to it as either an "un-mullet" or "a garden-variety skatertrash 'do." About six months ago the pizza boy commented that his brother had cut his hair like mine and asked me how long I'd had my hair like this. I told him. He emitted a low whistle and said "you've had your haircut for longer than my brother has been alive." "So what you're saying is I've rocked an uncool haircut for so long it's becoming cool again?" I asked. "I wouldn't go that far," he said, and laughed.
I had hair not quite to my shoulders when I was 18 (I'd been listening to too much Led Zeppelin). The thing is, I couldn't be bothered to actually care for it, so it always looked like a bit of a mess. When I got it cut to a normal length, pretty much everyone I knew complemented me on it and I realized pretty quickly that long hair wasn't a look I could do. I actually like the idea of having long-ish hair though. I like the feeling of the wind blowing through it (no, really), and I even enjoy having to blow my bangs away from my eyes. Every couple of years, I let it grow out a bit before I realize that I can't quite make it look good, and I think I'm in the process of doing that right now. That, or I've just been too busy to make it to the barber.