If productivity gurus agree on one thing, it's probably this--waking up and immediately grabbing your phone is a terrible idea.

"When you dive straight into emails, texts, and Facebook, you lose focus and your morning succumbs to the wants and needs of other people," warns author Travis Bradberry in one representative post.

"Author Julie Morgenstern wrote an entire book on the subject, called Never Check Email in the Morning," The Huffington Post reminds readers in an article that rounds up several voices all agreeing with Morgenstern and Bradberry.

But while "no email in the morning" is one of the most oft-repeated productivity tips, that doesn't mean absolutely everyone is willing to go along with this sage bit of wisdom. Marketing strategist and Harvard Business Review contributor Dorie Clark, for one, remains skeptical. On the HBR site recently, she dissented from productivity orthodoxy, claiming her "new research-based innovation...is to always do email in the morning."

Why you should start your day with your inbox.

Clark's reasons for going against standard advice are a mix of the personal and scientific. In her own experience, she notes, waiting to check email wasn't a productivity panacea at all. In fact, putting it off until she was mentally worn down later in the day made matters worse.

"Believing in the gospel of 'doing the most important tasks first' and pushing email correspondence to the end of the day, I found that I consistently avoided answering certain messages because they required hard choices that my brain found taxing," she relates.

Clark discovered that later in the day she simply didn't have the mental juice to force herself to confront emails that involved tough decisions like should I say yes to this commitment? Or how can I get out of this responsibility tactfully? Therefore, these messages languished in her inbox for far too long.

She explains that her personal observations are in line with the science of ego depletion pioneered by psychologist Roy Baumeister (science, it should be noted, that's recently been called into question). This research "has repeatedly shown that one's rational decision-making capacity is finite and declines throughout the day," Clark writes.

In other words, science says your brain is to blame for your trouble making decisions late in the day. Often, it's better to try to choose earlier, which makes dealing with email in the morning not only defensible but rational.

The practitioners versus the gurus?

Clark's advice might be a radical departure from the usual prescriptions of productivity experts, but apparently lots of other highly successful professionals also happily ignore the standard advice on the subject. "One recent survey found that the first thing most executives do in the morning is check their email," reports Jenna Goudreau, for instance.

Who do you think has it right on this--those in the trenches happily grabbing their phones first thing in the morning or the productivity experts warning us to put them down until later?