They’re convenient. They let us work anywhere and anytime. But they also play on our anxieties and insecurities and leave us much more bound to work than we used to be.

My research shows that people use their smartphones so much outside of business hours—reading and responding to streams of messages from the office—that many end up putting in 13 hours or more a day. But they’re not doing that extra work because they want to. They’re doing it because they feel compelled to, and because the smartphone makes it so easy.

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