The only common factor in all 22 MCU movies in the last 10 years has been the mid and post-credit scenes.
That is about to change with Avengers: Endgame.
Don't worry. There are no spoilers here. But yeah, for the first time since the inception of the Marvel Cinematic Universe, there will be no post-credit scenes.
And it makes sense. Endgame is the end of Phase 3 of the MCU and will effectively conclude the Infinity Saga.
So there is nothing left to tease before Phase 4 begins.
So the choice is yours. You can either sit through the credits to hear that sound or walk off. Personally, I am going to wait till they throw me out of the theatre.