The music Welch and Rawlings have been making across acclaimed, award-nominated albums these past two decades is a contemporary extension of traditional American genres such as folk, blues, country, bluegrass and even hints of early rock'n'roll.
But though their audience has grown in line with the plaudits and decent, if never spectacular, album sales, she freely concedes their songs can be demanding: the music can be spare and measured, the stories dark, the characters within them troubled, tortured or struggling.
"Yes, you have to slow down and make a bit of space in your life for it. Happily, once people do that and let our quiet panoramas unfold, then it seems to sink in really deeply.
"I have a great respect for our audiences because I think they love music and are well-listened, I always feel of anybody at any of our shows that I could sit down with their record collection and have a real good time."
Such a collection would probably include early Neil Young albums, country legends like the Louvin Brothers, the Carter Family, Bob Dylan, Ralph Stanley and the Elvis of Long Black Limousine.
Although she and Rawlings have released albums under her name and perform in Auckland as a duo later this month, their most recent outing, Nashville Obsolete - named for their adopted hometown where they own the handsome studio where Young recorded Comes A Time - is credited to the Dave Rawlings Machine, the second under that moniker because it puts him to the fore and allows them to invite in guest players.
"It doesn't take any weight off me as a songwriter," says Welch, "because we still write them the same way as we do for a Gillian Welch record, but it definitely gives us more breadth, which is what we are looking for.
"Because any time we put out a record under my name it's what we call a duet record, it's pretty intense and focused."
She admits that before her previous album The Harrow and The Harvest in 2011, she was dissatisfied with their songs and the direction they seemed to be going in. So they scrapped all the sessions and started again.
As a graduate of songwriting classes at Boston's Berklee College of Music, she is a harsh critic of her own work.
"[At Berklee] I learned you should never give in to cliche. Stay away from cliche unless you are doing it knowingly and for a reason. That's the worst kind of laziness and it's going to hurt you in the end.
"Cliches go by and that's when people tune out, and you never want a listener to tune out. You want them to stay right with you line-by-line, word-by-word. You gotta try never to lose them."
So even if the material errs on dark side of life - which she says is the area that most attracts her - the songs have to be true and connect with the audience.
"A lot of our material acknowledges life's more challenging moments, but I feel the people in the songs are not quitting or giving up: there is a perseverance and stoicism. Even in a dark or sad song I feel the person is going to make it through.
"So it's okay to take four or five minutes and be in that place, because part of getting through it is understanding that it is happening and accepting that.
"I always gravitated towards tragic, darker and slightly heavier songs. They meant a lot to me, a window on a world I needed to understand as a part of life. That works for a lot of people.
"The blues are for real," she laughs.
And so are the rewards for taking people there. Just before Christmas she and Rawlings - who haven't played in New Zealand since 2004 - were presented with a Lifetime Songwriting Achievement Award from the Americana Music Association in Nashville.
"It was very flattering and a nice surprise. I think we were too young to get a lifetime achievement award. One of my friends called it our Mid-lifetime Achievement Award .. but we took it seriously and it was an honour to get it with the other people being acknowledged [among them Lucinda Williams, Shakey Graves, and Los Lobos].
"We interpreted it as, after a 20-year career, people liking our body of work and valuing the songs.
"I'm gonna take it as a 'keep up the good work' thing."
Who: Americana singer-songwriter Gillian Welch
What: An Evening with Gillian Welch (and Dave Rawlings)
Where and when: Civic Theatre, Thursday, January 28
Essential albums: Hell Among the Yearlings (1998); Time: The Revelator (2001); The Harrow and the Harvest (2011); Nashville Obsolete (2015, as Dave Rawlings Machine)
