To start a new aloe from a spike do I tear or cut the spike from the old plant

Um, I don't think I've ever heard of starting one like that. But I am a new gardener and didn't know you could start roses from cuttings either and you can start a rose from one. Is the old plant dying? Or is it someone elses and you would like one of your own that is the same? I guess I'm just wondering if there is a reason you can't wait for it to have a baby?

I am new to gardening as well, I have an Aloe my research and the advice of these good folks here have said you can't start a Aloe from just a spike,It has to be from a baby that comes up from the roots, and the plant must have fairly crowded roots produce babies. If I am wrong I hope someone will correct me.