Labor unions, advocacy groups and even coffee shops have their own apps. And plenty of campaigns have followed suit — both major party presidentials had one last cycle — but their adoption down-ballot isn’t as widespread.

In fact, digital shops which offer the service of developing campaign-specific apps say it remains a hard sell. That could change ahead of 2018. One app vendor, uCampaign, which produced President Trump’s campaign app, says it’s done more business in the first quarter of 2017 than in all of 2016.

Thomas Peters, CEO of uCampaign, said his company has developed apps for advocacy groups including the NRA, Generation Atomic, and a presidential candidate in Costa Rica. But he still finds it difficult to sell down-ballot U.S. campaigns. “Congressional, mayor and local races have been a little bit harder to break in. It’s not always clear who to talk to,” he said.

Part of the challenge facing campaigns looking to develop their own app is the product’s shelf life. Even after people have downloaded the app, convincing users not to delete it is difficult. One study has pegged the shelf life of consumer apps at less than 30 days.

“It’s one of the biggest myths you have to dispel,” said Peters of the shelf-life worry.

Peters noted that those who’ve download a campaign’s app are its most ardent supporters and that the cost, which another consultant estimated was $7,500 for a basic app, is set off by the data that can be gathered.

“You pay a little bit more than you would to get an email, but you also get them to do other activities,” Peters said. He also noted that the address-book feature of his company’s apps, which checks a user’s contacts against the voter file, can identify up to 30 more supporters.

“If you’re not using an app, you’re missing out on an engagement opportunity,” he said.

Moreover, Peters argued that it isn’t significantly more work for a campaign to create content specifically for an app, which is what drives engagement.

He said his firm works with the digital agencies hired by a campaign, which are typically the ones already producing the copy. That copy is what gets turned into a daily content push to the users. “Engage with them everyday because these are your top supporters,” said Peters. “If you remind them [to take an action], they will do it.”

Once supporters complete an action on the app, they can get rewarded with titles, or digital trophies. “It becomes a social capital thing,” said Peters.

If a campaign is exploiting an app’s newsfeed, users start to use the app as one of their go-tos for information, he added.

Brian Ross Adams, a digital consultant to down-ballot Democratic campaigns, isn’t convinced that apps are worth the investment. “I would rather spend time and resources engaging with supporters on the apps they already use, rather than try to create a community around a new app,” he said.

But count Joe Lakin, digital director for the GOP firm Victory Enterprises, as a consultant who sees the potential of campaign-specific apps.

“I don’t think we’ve seen apps really used to their full extent beyond the presidential,” he said. “We’re hopeful that will change. It takes time.”

Though Lakin discouraged campaigns from turning the channel into a mirror of their websites.

“You need to provide things that are specific to mobile,” he said. For instance, Lakin noted that apps are a great way to push campaign merchandise, whether for fundraising or a way to motivate supporter engagement.

Exclusive talking points are another feature that can enable users to become campaign ambassadors. If there’s a continuous flow of content, according to Lakin, the users are less likely to delete the app.

Now, this cycle could see wider adoption of campaign-specific apps, Lakin said. “If campaigns don’t keep up with consumer brands, they’re going to miss the boat.”