The entry-level Apple Watch sport model - which starts at $349 - has been the most popular among early shoppers, according to data from Slice. But an extra band - which fetches as much as $149 for the quilted leather loop and $449 for the stainless steel link bracelet - can raise the cost considerably.
The popularity of spare bands suggests some consumers may be spending more on the Apple Watch than they intended.
"It's just a psychological thing," said Carolina Milanesi, chief of research and head of U.S. business at Kantar Worldpanel ComTech, a consumer research firm. "I start with the least investment, and then I spend more money, but I get something else."
Former Apple executive Jean-Louis Gassée, for example, went with the sport model for his starter Apple Watch, reluctant to invest too much in a first-generation product.
But he did not skimp on bands, purchasing a black quilted leather loop and a white sport model. He reaches for the leather for business meetings and swaps it out for the rubber model when he heads to the gym.
Distinctive bands help customers match the watch to their outfits and lend the gadget a more personal feel, which is key to the appeal of wearables, said Allen Adamson, who is chairman of North America for Landor Associates, a branding firm.
"Apple needs to win the functional war, but they also have to win the fashion campaign and make it fun to wear," he said.
Apple has opened the door, creating a platform for third-party developers to design bands of their own. Apple will not share in the revenue from sales of those bands, according to a person with knowledge of the matter.
If bands designed by outsiders take off, that may make a dent in sales of Apple's own accessories. But having a stylish array of bands to enhance the appeal of the watch is most important, experts say - the extra revenue for Apple is just a fringe benefit.