You can use the Present Perfect Continuous to talk about a situation or activity that began in the past and has been in progress for a time until now. There are times that you can use the Present Perfect Continuous with expressions that show the time period (for example with since and for):
The tournament has been running every year since 1930.
Construction workers have been saying for years that the library building should be knocked down.
I've been meaning to buy Mary a gift since I heard she was having a baby shower.
You can often use the Present Perfect Continuous when you ask questions with How long …? and when you say how long something has been in progress:
How long have you been staring at me?
How long have they been living next door to you?
The price of gas has been rising since the war started with Iraq.