Apple Inc. sold twice as many Watches as iPhones in each device’s debut year. Yet the smartwatch is dogged by a perception that seems premature given the history of Apple’s most popular devices: disappointment.

As the Watch marks its first anniversary on Sunday—two days before Apple’s quarterly earnings announcement—the product’s fate is critical to the company. It is Apple’s first all-new product since the iPad and a test of its ability to innovate under Chief Executive Tim Cook, when sales of iPhones are slowing.

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