My mom has one going on 3 years now. It's getting quite large and she forces it to bloom every year (not sure the # of hours daylight/dark.) So I kept my little red one from this year (which I nearly killed half a dozen times letting it get too dry.) I'm going to repot it into a sturdier pot because I think the cheap pot had a lot to do with it. I heard that I was supposed to cut it back to about 6" tall...can't remember now where I heard that. I went ahead and cut mine because it was lanky and dry on top. Maybe someone else can weigh in on that.
I still have my poinsettia as well, in the past when I had them they would die within weeks after Christmas was over. But this year its doing well, I think it's about keeping it in full sunlight and not watering it too much.