David Letterman has lingered onstage for longer moments these days at the Ed Sullivan Theatre, where his 22 years hosting Late Show with David Letterman are coming to a close on Wednesday night (he hosted Late Night on NBC for 11 years before that).

“So when I’m down here during band numbers or during commercial breaks, I will go to various places and — and try to memorize what it looks like and how I feel, and look at the audience and — and get the scale of things because even though I’ve done it for so long, I — I don’t ever wanna be without a fairly accurate, fairly vivid impression of this experience,” Letterman told Jane Pauley for CBS Sunday Morning.

Letterman worked with Pauley in local TV news in Indianapolis in the early 1970s before both made it big. She recalled him telling high-school students there this once about his success: “You said, ‘It’s like robbing 7-11s. The money’s good, but you know you’re gonna get caught.'”

Letterman’s reply now?

“I hope I said that. In those days I was — probably not you — waiting to be tapped on the shoulder, ‘Okay, the real guy’s here. You can go home now.’ That’s — that’s what I was always motivated by, that fear — the fear of failure. And then I have to, ‘Oh darn.’ And then, you know, I wasn’t chosen again so I go back home. That was always the concern.”

Other revelations:

Letterman said he’s a recovering alcoholic, having stopped around the time he began hosting Late Night in 1982.

“I guess you’re always an alcoholic,” he said, “Yeah.”

“It was that old thing where my dad used to like scotch and soda. And, ‘Here, here, Dave, you wanna try one?’ And I tried one. And I just thought, ‘This is fantastic.’ … It was delightful. I — I just — I loved everything about it.”

“But then in high school it– it was part of the culture. And in college, it was mandatory. And then when– when you get outta college people start to taper off. And I was surprised. I would look around and [ask] ‘Where are all my drunk buddies?’ And you had to go looking for a drunk buddy here and there. They weren’t prevalent the way they were in school. And I drank right through ’til I was 34. And I had the — the show at NBC and I just said to myself, ‘You’re- – you’re a fool, you’re a dumb fool. You can’t do this. You — you know, they just don’t give these shows to everybody. You have one. And– and you drink yourself into trouble, you’re done, pal.” And I just quit. Never, never took another drink.”

“It was huge — because I’d be dead. I — I’d just be dead.”

Letterman doesn’t know what retirement will mean for him, and that’s a bit scary.

“I’m naked and afraid because — and I, it’s so cliché, but I’ll share it with you anyway — any enormous uprooting change in my life has petrified me. Really petrified me. But once I’ve come through the other side, the — the reward has been unimaginable.”