I have been playing CSS for 5 years already. I continue playing this up to now. I have played CSS for 5 years already. It has meaning that you play it, because of already.Indeed, I 've just finished playing it and there is a possibility I don't play it anymore. Also you can stop playing it but it's obvious or has result that you played.
You're welcome. You should use it only when the duration of action is pointed.
I had been working for a whole day when my brother came. He has been teaching English since 1980.
Notice both of them can be used if the action, expressed by Perfect Continuous Tense, has finished right before general action, expressed in Simple Tense. But it's rarely used.