If it's Monday it must be Berlin. Diana Krall is deep into a year-long world tour that will take her into the middle of the year.
Just before she played four triumphant, sold-out nights at the Albert Hall, I found myself sitting in a hotel suite overlooking Berlin's Brandenburg Gate.
Krall had arrived in Europe after a week in Australia and a flight via North America; the two days she managed at home in Vancouver as a stopover were her first for about six months. "More dental work!" she quipped.
She was feeling the effects of such an intensive itinerary. Plain-speaking to the point of being blunt on occasions, and quick to deploy her native wit at her own expense, Krall has never been one to wave a showbiz wand over her life.
"I've had a rough month. I was really sick - eight shows in nine days and then I fell over, stayed in bed in Madrid for three days, still did the show, crazy scenes, couldn't sing because I was still getting over this cold. It's sure different from playing the Court Theatre in my hometown."
Krall may be porous with travel-fever, but she's still convinced it's where she ought to be. "No way I'm complaining," she insists. "This is what I choose to do. I know just how lucky I am."
Krall's whole career is founded on an unrelenting work ethic underpinned by the notion that the way to get lucky is by "doing your homework.
"I grew up with the idea that if you like somebody's music and you want to play with them, then you work very hard at learning all their tunes and maybe someday you'll get to play with them.
"It was a dream since I was 16 to play with people like [drummer] Jeff Hamilton or [bassist] John Clayton and it took until 2001 for it to happen, on a touring basis. It took a long time and a clear vision of what I wanted to do.
"We did Australia together this time around, and I was still looking to them as mentors. I met [jazz pianist] Marian McPartland for dinner recently, a fascinating woman, and so full of information about the music. It's easy to think, 'I feel so intimidated I'm not gonna talk to these people', but you have to get past that feeling. Talk to them. Learn from them. It might not happen again."
Such clarity of purpose continues to fuel her career. Her spring 2004 album The Girl in the Other Room, which triggered her latest worldwide tour and which included songs by Tom Waits and Mose Allison, as well as a raft of pieces written with her husband Elvis Costello, signalled a major shift from her previous approach.
Some felt it to be a repositioning closer to what could be termed jazz's recent "acoustic mainstream" phenomenon - Norah Jones, Jamie Cullum and their ilk.
Yet to make such assumptions is to misread Krall's motivations.
She is aware of her contemporaries, but she does not regard them as rivals, nor are they pointers to some new approach for her own career.
The Girl in the Other Room came about because of the personal circumstances of the time - the loss of her mother, her marriage to Costello, her search for ways to express these changes in her life. Songs from that album appear in her set next to Night and Day or Let's Face the Music and Dance.
The tour is now top of her agenda, and Girl is already in the past.
"Sure, those songs mean a lot to me personally," she reflects, "but I don't find them any more interesting or challenging to perform than But Not For Me." She's mulling over three or four new projects to take on after the tour.
The DVD of her Montreal set is the latest snapshot of a moment in time, rather than something she's hanging her career on.
It distills what the tour was about - this stage of her development as a musician.
Of her contemporaries, she says, "I didn't come up with them, but I admire them. I like Jamie Cullum because he acknowledges that he's learning and he's trying to get better and he's up front about how he feels about what he's doing.
"Same with Norah Jones. I read a few interviews with her recently and I really like her attitude and what she's doing. I think her success is very admirable. She's got it - you just know when you hear her. Once in a while someone like her comes along who has that maturity and who's got that something special.
"Cassandra Wilson has that, too. She's the ultimate jazz singer today. She has it all. Then there's Dianne Reeves, Abbey Lincoln, Patricia Barber ... " Krall's idols include Joni Mitchell and Nat Cole, but she was also encouraged early on by mentors such as the pianist Jimmy Rowles and the bassist Ray Brown.
London and her favoured concert venue, the Albert Hall, have unique resonances for her.
The city is where she and Costello were married, and where many of their mutual friends still live.
As for the Albert Hall, "it's a very special place for me, personally and professionally. It's such a beautiful building, isn't it? And huge!
"I didn't realise how huge it was until I went to the concert for George Harrison. I was sitting there thinking, 'Oh my God! This place is overwhelming!', but it's different when it's you who's doing it.
"When you're sitting there up on the stage it's dark and you can make it into a club feeling, you can create that intimacy.
"I know what to do now, to avoid being overwhelmed by it - you don't over-sing to the hall. You know it's a big place, but you have to pull people in, rather than go all out."
This is exactly the approach she takes on the DVD in front of an even larger crowd than that facing her in London.
She appears on stage with her tour group, including the brilliant young guitarist Anthony Wilson, and plays up a storm of music where her singing and piano playing seem a natural extension of each other, and then she walks off with a brief wave.
The only thing the DVD doesn't include that was paraded successfully at the Albert Hall is the most recent development, solo stride-piano outings.
As Krall said in Berlin: "I'm pushing myself all the time, practising a lot. I'm even playing some solo piano now in our sets.
"It gives me a good kick in the behind, and that's what I want. No slacking! You do what you have to do to inspire yourself, because if you're not inspired, the audience can tell in a second."
Remarkably, in a world of pandering to marketing ideas of what music should sound, look and taste like, Krall's instinct for the kind of music she wants to create continues to coincide with the needs and desires of her worldwide audience.
Yet for her, it remains a simple equation.
"You have to trust your audience. Just be honest with them and they'll always respond. You can't talk down to them, you have to trust that they're going to love it because you love it."
It's worked beautifully so far.
* Who: Diana Krall, jazz singer-pianist
* When and where: Aotea Centre, Monday April 25; Michael Fowler Centre, Wellington, Wednesday April 27; Christchurch Town Hall, Friday April 29