As more and more consumers come to depend on mobile devices to keep up with friends, monitor their finances, read the news—to live their lives, really—it’s increasingly important for brands to make sure they have the digital tools they need to reach their audiences in an agile, data-driven way.

Unfortunately, the truth is that a lot of marketers are trying to engage today’s audiences with yesterday’s marketing technology. That will put some brands at a major competitive disadvantage. The divide between what’s possible to achieve with the marketing technologies that exist today and what marketers can do with the tools they’re actually using is known as the martech gap, and it’s particularly worrisome when it comes to mobile.

Ten years ago, mobile as we know it didn’t exist; today, mobile has surpassed desktop in a big way and is busy reshaping every aspect of our lives. That makes addressing the mobile martech gap essential for any affected marketer.

What’s causing the gap?

A number of factors, but the main one is money. According to a study on martech done by Walker Sands Communications, 42% of marketers are working with marketing technology that’s out-of-date and impeding their ability to do their jobs effectively. And 69% of marketers said that budget limitations were the main factor holding their brand back from implementing up-to-date marketing technology.

While there’s a lot of talk about the primacy of mobile among major brands, too many companies aren’t prioritizing mobile martech when they’re making decisions about how to allot their money.

Why does the gap matter?

A you know, mobile isn’t just a trend or a fad. People spend the majority of their digital device time each day on mobile and sleep with their phones within reach. Mobile and related commerce reportedly generated more than $3 trillion in revenue worldwide in 2014 and contributed $548 billion to the U.S. gross domestic product. A brand that’s not responding to the changing landscape today is acting like a company that ignored the promise of the web back in the mid-90s—shortsighted and possibly doing itself long-term harm.

How to close the gap

Closing the gap requires, of course, getting the right mobile marketing stack for your brand—CRM, automation, analytics, and a process (or platform) for connecting it all. Budgeting for mobile martech starts the same way budgeting for anything does—determining the ROI of the cost. Here’s why brands can’t afford to pass on mobile martech, and why investing in martech will generate a real return.

1) Doing nothing IS an option, just not a good one

Companies are run by people and people tend to keep the status quo in place unless circumstances force a change. That means a company that is underinvesting in mobile martech (or maybe not investing at all) may well continue doing so until the negative impact of that decision becomes so clear that it’s impossible to ignore.

Maybe new user acquisition has flattened out. Maybe you’ve started falling behind a competing brand that invested the time and money to get the mobile martech they needed to effectively engage, retain, and monetize the customers they already have. But if you wait that long, it’s going to be a lot tougher for your brand to outcompete rivals that are already up to speed on the latest mobile martech innovations.

2) You could build your own mobile martech… but there are big downsides

For brands that recognize the value that mobile martech can provide but are reluctant to set aside the money to purchase mobile marketing automation platforms and other tools, building their own versions in-house can seem like a good compromise. But of course, building your own martech isn’t cost-free.

A you may imagine, the developer time and effort that it takes to put together something as powerful as the martech that’s commercially available is significant—and it’s the rare firm that has engineers sitting around with nothing to do. Every hour that your developers are creating your proprietary mobile marketing solution is an hour that they’re not spending supporting your brand’s core product.

And despite all that time and effort, there’s a strong chance that what you’ll come up with won’t be as robust or up-to-date as the martech you can buy; after all, your brand is trying to do as a side project what mobile martech companies focus the majority of their time and energy on. What’s more, since martech companies must gain and retain clients, it’s in their best interest to continue innovating and add frequent updates. Odds are that martech companies with a robust support team will even already have experience addressing problems like the ones your brand is facing, and they can help you implement a faster and more complete solution than your team could alone.

3) The ROI on mobile martech can be huge

Mobile martech is an investment. And if you’re going to make that investment, it’s important to ensure that the tools you’re buying will help your brand meet its marketing goals. What those goals are will differ by vertical and among brands, but, at minimum, you need to be able to:

• Reach your customers effectively on their mobile devices
• Engage them with your brand promise and the possibilities you offer
• Retain them as members of your audience
• Convert your customers along whatever metrics are most important to your brand

Reaching those goals doesn’t just support the kind of strong customer relationships that will keep your brand competitive going forward—it will also obviously have a major positive impact on your bottom line. One brand that invested in the latest mobile martech was able to use it to identify a segment of their audience that was engaged with their brand but had never made a purchase, then send those customers a single in-app message that generated $100,000 in new revenue.

The newest mobile marketing tools are allowing brands to connect with customers with more efficiency and at higher returns, and that’s worth investing in.