Fitness trackers, such as the Fitbit or Jawbone, are popular accessories for health-conscious people, but their days may be numbered. Many next-generation smartphones are shipping with the ability to track steps, calories, heart rate and more, which industry experts say could make fitness trackers obsolete.

New Samsung phones, such as the Galaxy S5 and the Galaxy Note 4, come with S Health, a fitness- and health-tracking app that has all the capabilities of a wrist-based tracker. LG has a similar app, LG Health, on its G3 phone, and smartphone manufacturer HTC partnered with Fitbit on its last flagship phone, the M8, which offers users similar fitness-tracking features.

The fitness tracker business is booming and is now a $330 million industry. With the features of these devices becoming accessible to everyone with a smartphone, that number will continue to grow, says Pankaj Kedia, senior director of product management for Qualcomm, a manufacturer of processors, sensors and other cellphone components. “Fifteen percent of U.S. consumers currently use a wearable device like a smart watch or fitness band,” he says. “As wearable devices continue to add new features and services, [the industry] will continue to draw in consumers.”

But as more and more smartphones boast these features, experts predict that wearables could go the way of the dodo, since most consumers prefer to eliminate redundancies and do all their business on a single device. Especially a device they already own.

Phones now track steps and calories with the same accuracy of wrist-worn trackers, making them attractive to people who are simply trying to quantify how much they move during their day – the vast majority of users, says Ritu Agarwal, who heads up information systems at the University of Maryland. But for athletes and serious runners, there’s no replacement for traditional wrist-worn trackers – yet.

“Some professional runners would like to measure their heart rate while running,” she says, which can only be achieved by wearing heart-rate strap accessories that often come with these trackers; smartphone sensors, meanwhile, require stillness to get an accurate reading. Still, says Agarwal, "these are temporary constraints that smartphone manufacturers are proactively addressing.”

The biggest problem smartphone manufacturers need to solve before they dethrone wearables is battery life, Kedia says. A Fitbit can go for a week without charging. A Jawbone UP can last as long as 14 days. Yet even the smartest smartphones need to be charged every other day. “Fitness-tracking capabilities in smartphones require fast, reliable connectivity to sync and enable features such as navigation to track your run and offer real-time updates on your progress to social networks,” he says. “It’s a challenge to do that while keeping your battery alive.”

As battery life improves, Agarwal anticipates that these phone features will become more popular and trickle down to cheaper phone models. However, rather than stripping wearables of their fitness-tracker-of-choice title, Agarwal expects that smartphones and wearables will learn to work together to produce the next-best products. “At the moment the common view is that they are separate devices,” she says, “but there is no compelling reason for them to be that way."

Kedia agrees, adding that wearables have one important attribute that smartphones simply can’t compete with – their small size. “People will use a combination of smartphones and wearable devices to get the optimal experience,” he says. “Wearable fitness trackers are most often an extension of the smartphone, but they allow you to enjoy step tracking and other important functions without having to keep your phone out at all times.”

While it can be cumbersome to have to hold your phone incessantly, having a device perched on your wrist lets you see the stats you want with just a tap. “Wearable devices offer instant, continuous, hands-free access to the most relevant personalized information,” Kedia says, “which empowers us with more efficient and effective ways of managing our daily lives in a way [we] can’t imitate with a smartphone due to portability.”