Technology is often painted as the key to the future. But some people are taking a step back and unplugging to preserve tech-free aspects of society.

To hear Tiffany Shlain talk about her “tech shabbat,” it sounds less like a fast and more like a banquet. “It’s so much more about what I get back,” says the filmmaker about her sunset-to-sunset breaks from screens on Fridays and Saturdays. “I feel like my whole day is extra long and wonderful.”

Prodding people to unplug for 24-hours each week may look like an odd stance for Ms. Shlain, who founded the Webbys, one of the most prestigious awards for internet content.

But she’s not alone. Tech-free retreats have become common among Silicon Valley’s elite. Even the famously tech-savvy Pope Francis said on Ash Wednesday that “Lent is a time to disconnect from cellphones and connect to the Gospel.”

Sunset on March 6 marks the start of the National Day of Unplugging, a 24-hour break from screens started in 2009 by the Jewish nonprofit Reboot. Past years have seen over 60,000 people participating. Ms. Shlain, whose book, “²⁴⁄₆: The Power of Unplugging One Day a Week,” was published last September, embraces this effort. Like many critics of tech overuse, she argues that always-available information feeds interfere with our fundamental need for mental downtime. “I just don’t think we were designed to be on ²⁴⁄₇, ” she says.

As technology becomes ever more entrenched in our lives, even some of its most ardent proponents are suggesting we step away from time to time. If we don’t, they caution, we may be unwittingly making a huge sacrifice.

“This really does touch everyone’s lives,” says Kim Cavallo, an ambassador for the National Day of Unplugging and the founder of lilspace, whose smartphone app rewards users for taking breaks from their phones with local perks and charitable donations. “It’s not any one particular religious group. We all feel the sense of disruption of human connection.”

A “detox” or a transformation? Many critics agree that unplugging for just one day will not, by itself, change your relationship with technology.

“I’m not a big advocate of extremes,” says Anastasia Dedyukhina, founder of the digital well-being training consultancy Consciously Digital. “It’s much more interesting to find a balanced way.”

Dr. Dedyukhina sees digital fasting as a first step in reclaiming our lives from tech overuse, but warns that, like many simple fixes, it can miss the bigger picture.

“It’s actually very dangerous to see this as a solution,” she says, “because the problem is not that we are spending too much time on the screens. It’s that so many of our functions are now outsourced to technology, and there’s no culture around this—what’s appropriate, what’s not appropriate.”

Computer scientist and self-help author Cal Newport agrees that unplugging can be a good first step, but warns that doing so needs to be seen not as a break—or worse, a “detox” —but as the first step in a transformation. “The reason to step away is not just to lose the habit of technology, but to give yourself back the space,” he says.

[A] feels that the daytime is not short but good and lonely.

[B] notes that he/she is a mild supporter and tends to find a balanced method.

[C] holds the opinion that the tech extensively influences people’s daily life.

[D] thinks that information feeds disturb the basic demand for mental rest.

[E] agrees that it’s beneficial for people to stay away from mobile phones occasionally.

[F] believes that detox is a great method to solve the problem of tech.

[G] points out that unplugging signifies a good start to a transformation.

Anastasia Dedyukhina