For many of us, nine months spent quarantining at home has completely erased the elaborate routines and habits we had carefully constructed in the Before Times. Commuting? Wearing makeup? Going to spin class? School drop-offs? Social distancing requirements and the closing of schools, workplaces, and businesses have upended many of those pre-pandemic habits.

So it’s unsurprising that as we turn to 2021, many Americans are seeking ways to develop new habits and bring some structure and routine back into their largely housebound lives. A new survey from CIT Bank (conducted by the Harris Poll) found that 43 percent of Americans are setting New Year’s resolutions for 2021, compared with 35 percent who did the same for 2020. Resolutions focused on habits such as exercise and self-care are especially popular.

When a new year starts, we’re filled with optimism and set ambitious goals, believing that all we need is a fresh start and soon we’ll get fit, learn Spanish, eat healthier, and save more money. But few stick to those resolutions past January: A study by the University of Scranton found that just 40 percent of resolution-makers are still keeping their resolutions six months in.

That’s where habit-tracking apps want to help you. A growing market of companies has emerged that claim to help you develop — and stick to — good habits. In the last few years, dozens of habit-formation apps have cropped up: Momentum. Habitica. Done. Coach.me. Habitshare. Habitbull. Today. Streaks. There are so many that the website Lifehack ranked 22 of the “best” options. Most of the apps are ad-free, but charge their users for the ability to create more habits, for more premium features, or for access to personal habit coaches.

Much has been written about the very modern obsession with the quantified self: logging data about every part of our lives, such as our water intake, our daily steps, our menstrual cycles, our caloric consumption. But habit-formation apps are a slightly different breed: They’re aspirational. Habit-formation apps are less about distilling your life into a series of data points and more about becoming your ideal self: If you use their app, you too can become a person who practices good habits. You can become someone who exercises and meditates every day and always drinks eight glasses of water.

But do these apps really work? Can they deliver on their promise to help you build better habits? Will an app really turn you into a person who gets up at 6 am every day to go for a run and make a smoothie? I asked some habit experts about whether these apps can really live up to their promises.

Gretchen Rubin, a writer who has authored several books on habits, told Vox there’s no one-size-fits-all approach to building better habits — so habit-formation apps can work, but only for certain types of people who respond well to them.

In Rubin’s book Better Than Before, she writes that most people fit one of four tendencies when it comes to habit formation: upholders, who are disciplined and respond to both internal and external expectations; obligers, who can’t keep commitments to themselves but respond to expectations from others; questioners, who ask why and can keep a habit if they understand the logic and reasoning; and rebels, who hate being told what to do by others — so it has to be something they want to do.

The Power of Habit, told Vox that “there’s a basic structure to habits, which is that there’s a cue, a routine, and a reward; this is called the habit loop.” Duhigg explained that the key to forming a new habit is “to diagnose what the cues and the rewards are that are driving their current habits and then to try to come up with cues and rewards for new habits. That matters much much more than whether you’re using a Fitbit or something like that,” says Duhigg.

For people who fall into the other tendencies in Rubin’s framework, outer accountability might not work. Rebels, she says, might find daily push alert reminders annoying, and then resent the app for telling them what to do. Questioners need to understand the rationale of why they should do something, so they might find habit-forming apps unappealing unless they’re backed by scientific research and explain their rationale. And even for some obligers, push notifications and reminders still might not be enough to motivate them to do the thing.

The cottage industry of habit-formation apps has tapped into different aspects of the psychology of habits in order to motivate users — whether that’s in the form of reminders, accountability, streaks, or coaching. And the reason why there are so many app options is related to Rubin’s theory of different habit-formation tendencies: No single style of app will work for everyone. So self-improvement-obsessed developers started creating their own apps to fit their own needs, and we ended up with dozens of different apps to sift through in the App Store.

Many of these apps, such as Done, Productive, and Streaks, rely on a “streak” feature — they track how many consecutive days you’ve completed the habit, and some users are motivated to keep their streak going as long as possible. This concept, often referred to as “don’t break the chain,” was popularized by comedian Jerry Seinfeld, who said it was his productivity secret.

Other apps offer accountability features to pressure you into completing your goal. Coach.me offers forum-like support communities around popular habits, so that users trying to, say, wake up earlier can talk to others with the same goal and hold each other accountable. Habitshare allows you to share your habit goals and your progress with your friends in the app, thus offering another form of public accountability.

Some apps, like Habitica, turn habit formation into a game: The app rewards users who complete their habits with badges and other virtual incentives. Plant Nanny, an app that encourages people to drink more water, displays a virtual plant that is “watered” every time you self-report that you drank water. If you don’t drink enough water, the plant starts to make sad faces at you and eventually dies. Like a 2019 version of a Tamagotchi, it’s habit formation by guilt trip.

Most of the habit-formation apps are, refreshingly, ad-free, but charge users in various ways. Some apps, like Streaks and Today, charge a one-time upfront fee, ranging from $4.99 to $9.99. Others, like Fabulous and Habitbull, charge an annual fee of anywhere from $19.99 to $49.99 a year. And several, including Done, Momentum, Habitminder, and Habitlist, let you create a limited number of habits for free but then require you to upgrade to a premium version for the ability to create unlimited habits, if you really want to go all-in on your self-improvement efforts.

Usually, these apps aren’t created by big, venture-backed startups; in many cases they’re built by a developer or two, or a small app company. Many of the developers behind these apps say they created them out of a personal need: They were facing a challenge in their own work or life and looking for a tool that would help them develop more disciplined habits.

Quentin Zervaas, one of the founders of Streaks, told Vox: “We launched the app because we wanted a really simple way to track a small number of things that we wanted to complete every day. For example, I was trying to write a book, but was finding it hard to complete, so I figured if I just completed a small amount each day, eventually it would be finished.” (Zervaas noted that he did indeed finish writing his book after building the app.)

Scott Dunlap, the founder of Habitlist, gave similar reasoning for starting his app: “I was looking for a habit tracker that had a clean, intuitive interface that could handle flexible scheduling options. I didn’t find one that worked for different situations — drink eight glasses of water every day, work out every Monday, Wednesday, Friday, water the plants every three to five days — so my streaks would inevitably end, and the app would actually make me less motivated,” Dunlap says. He eventually approached a friend and decided they would build a habit app themselves that had the features they wanted.

And Jenny Talavera, the founder of Done, was already designing and building educational apps for children. But when her husband was trying to quit smoking, Talavera told us, he couldn’t find an app that gave him what he needed, “so he asked if I could make him one. Three months later, Done was born.” Talavera added that at the time, “Most if not all habit trackers just helped you build habit. These habit trackers would let you create a habit and every day mark it done or not done, but they wouldn’t track something you didn’t want to do. He needed an app to help him quit a bad habit.”

Fabulous and StickK, were created at universities in conjunction with leading experts on behavioral economics. Fabulous was incubated at Duke University’s Center for Advanced Hindsight, which is led by Professor Dan Ariely. And StickK, an app that emphasizes the creation of a commitment contract, was created by Dean Karlan and Ian Ayres, then both professors of behavioral economics at Yale University. Karlan, who now teaches at Northwestern University, was inspired to start the app after his own weight-loss journey. Both StickK and Fabulous say they use research-backed approaches to habit formation.

Coach.me is one of the few apps that takes a different tack, both in its business model and its approach to habit formation. Launched in 2012 by CEO Tony Stubblebine and called Lift at the time, Coach.me was one of the early habit-formation apps on the market. The app has raised $3.6 million in venture funding and makes its money in a unique way: through habit-coaching services.

When you sign up for Coach.me and choose a habit, you are plugged into a support community of other app users so you can commiserate, support, and hold each other accountable to your goals. If you need an even more aggressive approach, for $19.99 a week or $65 a month, Coach.me will pair you up with a personal coach who will message with you every day to help you achieve your habit, like a personal trainer. Coach.me has developed a network of thousands of habit coaches, and users can browse through their profiles in the app and select a coach they like, much like a dating app.

Duhigg says that habit apps can work — but only if you actively monitor the data from the app each day and use it to analyze how you can change.

“People are actually less likely to develop new habits if they’re using a device to pay attention for them instead of paying attention themselves,” Duhigg told Vox. “But if you actually use the device and take its data and turn that data into knowledge, then it can actually improve your odds of changing.”

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