recently completed actions
She has tidied her room.(She has finished tidying her room. You can see it is tidy now. evidence in the present)
actions which happened at an unstated past time and are connected with the present
He has lost his keys. (He is still looking lor them.)
personal experiences/changes which have happened
I've lost 10 kilos.
emphasis on number
She's written three letters since this morning.
She has called on two clients since 12 o'clock.
Present Perf. Cont.
actions started in the past and continuing up to the present
He's been writing a letter for two hours. (He started two hours ago and he's still writing it.)
past actions of certain duration having visible results or effects in the present
She's been crying. (Her eyes are red.)
actions expressing anger, irritation, annoyance, explanation or criticism
Who has been using my toothbrush? (annoyance)
emphasis on duration (usually with for, since or how long)
She s been calling on clients since this morning.
Note : live, feel and work can be used either in the Present Perfect or the Present Perfect Cont. with no difference in meaning. I've been living/I've lived in Rome for a year.