Editor's Note: This is part of a series of pieces looking at the year to come that Mobile Marketer will publish throughout January. For more on what to expect in the months ahead, check out our rundown of five of the year's top trends and how mobile and retail will converge going forward.

Across any and all metrics, mobile continues to play a bigger role in consumers' lives. In 2019, people downloaded 204 billion apps, a 45% lift since 2016 — excluding reinstalls and updates — and consumer spend on apps hit $120 billion, more than doubling since 2016.

These eye-popping statistics and more are revealed in App Annie's State of Mobile 2020 report, which highlights several trends marketers must pay attention to as mobile ad spending jumps 26% to $240 billion this year.

"We're finally seeing a big push with mobile ad spend," Amir Ghodrati, App Annie's director of market insights, told Mobile Marketer. "For a long period of time, [mobile] time spent continued to grow, but ad spend on mobile has been significantly lower than what you'd expect, considering how long people spend there."

For Ghodrati, marketers continuing to invest in mobile is common sense.

"If this is where everyone is spending their time, and you have a better sense of who users are, why wouldn't this be your primary channel for reaching users?"

Generational differences

For brands, App Annie's biggest takeaway is how much the mobile landscape is moving toward Gen Z, the first truly "mobile generation."

"As [Gen Z] spending power grows, they're starting to establish consumer habits and brand loyalty on mobile," Ghodrati said. "If you're trying to set yourself up for the future, you need to set yourself up for success for Gen Z now before those habits are established, because it's going to be harder to switch someone from one service to another."

However, mobile consumers have different expectations from brands and interact with businesses on their own terms. What works for Gen Z doesn't necessarily work for other generations, and vice versa. And while Gen Z is driving the average daily hours spent on mobile devices, mobile usage is also increasing for older generations, requiring brands to have generation-specific strategies in place.

"Millennials and Gen Z have over $1 trillion in direct spending power, and will continue gaining influence in 2020 and beyond," Kathleen Gambarelli, Snapchat's group product marketing manager, said in the report, calling on brands to seek out mobile experiences that drive incremental reach among younger consumers.

IoT comes into focus, gaming surges

While on the minds of mobile marketers for years, 2020 could finally be the year when Internet of Things (IoT) apps cross over into the mainstream.

"We're starting to see an uptick in IoT and connected devices," Ghodrati said, pointing to the 67 million downloads for the top 15 IoT apps in 2019 that encompass voice assistants, streaming video services, in-car features, fitness devices like the Fitbit and home security systems like Ring.

Mobile is the "brain" of all these devices, which increasingly will be a part of consumers' lives; by 2025, there will be 25.2 billion connected devices online, per the report.

Meanwhile, mobile isn't just for operating the devices in consumers' lives, but a key part of their downtime as well. A major piece of mobile since the beginning, mobile gaming has progressed significantly and is set to surpass $100 billion across all app stores this year.

Mobile gaming continues to expand its lead — basically 25% higher — over the consumer spend on all other forms of gaming, whether via home console, personal computer or handheld. Subscription-based gaming offered by Apple Arcade and Google Stradia has the opportunity to expand the pie, Ghodrati noted.

Keys for brands in 2020 and beyond

As consumers spend more time and money on mobile, marketers must match that by taking advantage of mobile innovation. Ghodrati suggested that marketers experiment with ads targeted at mobile audiences and analyze what resonates, whether that means optimizing ad orientation for mobile viewing or offering ads that work whether a device's sound is enabled or not.

"For mobile, it's even more important to get someone's attention quickly," he said. "[Brands] need to show the value of what your app provides — not just the value of your service… What special functionality am I getting, or what about it will make my life better or easier?"

Mobile engagement begets more mobile engagement. "When you have that app on the device, you can send push notifications or run reengagement campaigns," he said. "Getting the app installed on a device is such a huge win, [because] most people are not going to uninstall unless its negatively impacting mobile experience."

With improvements in smartphone battery life and the increased reliance on cloud storage, getting an app on a device often means it will stay there. In the months ahead, savvy mobile marketers will capitalize on that.