What research says about building lasting habits

Written by Julie Stewart (opens in a new tab)

Medically reviewed by Ecler Ercole Jaqua, MD, MBA, DABOM (opens in a new tab)

Key points:<ul><li>The more habits you try to juggle, the more vulnerable your routine becomes when life gets messy.</li><li>Consistent action over time rewires brain circuits until behaviors become automatic.</li><li>Missing a day doesn’t break a habit; what matters is quickly returning to the desired behavior.</li><li>Behaviors tied to your values and daily routines eventually become part of your natural, automatic rhythm.</li></ul>Spend enough time optimizing your health, and one thing becomes clear: The more dials you try to turn at once, the harder the whole system is to manage.Habits like getting morning sunlight, doing more Zone 2 cardio, tracking macros, and dialing in hydration are all solid moves. But stack enough of them together at one time and you end up with a new routine that only works when life is perfectly controlled.Real life is messy, unpredictable, and chaotic. When it intrudes — travel, injury, a sick kid — complex routines can quickly fall apart. After a bad night’s sleep you skip your run, which makes hitting your protein goals feel pointless, so why not have that second cookie…"Your system is designed to cope with intensity but not complexity,” says <a href="https://chriswillx.com/" rel="noopener noreferrer" target="_blank">Chris Williamson</a>, host of the Modern Wisdom podcast. “When life gets complex and you're trying to juggle too many things, that's when you fall off."Williamson has interviewed hundreds of people at the top of their game: athletes, psychologists, physicians, relationship experts, business owners, and more. Often, the conversations turn to the habits and routines that make them successful. One pattern shows up again and again: An all-or-nothing approach to habits doesn’t work. Success involves being realistic about the time you can commit, building structures that help you stick to your plans, and forgiving yourself quickly when things go sideways.The framework below draws on that idea — and the research behind it — to show how lasting habits form.<h2>Commit to 90 Days</h2>“In my experience, habits tend to take between two and three months to properly lock in,” says Williamson. His simple rule: Stick with a new habit for 90 days. Research suggests habit formation timelines vary widely, but roughly two to three months is common for many behaviors.<a href="https://www.sciencedirect.com/science/article/pii/S0001691824000544#s0005" rel="noopener noreferrer" target="_blank">Motivation</a> alone won’t get you to your goal. It fluctuates with your <a href="https://pmc.ncbi.nlm.nih.gov/articles/PMC5682236/" rel="noopener noreferrer" target="_blank">mood</a>, how much <a href="https://www.tandfonline.com/doi/full/10.2147/NSS.S368335" rel="noopener noreferrer" target="_blank">sleep</a> you get and even <a href="https://psycnet.apa.org/record/2011-28783-001" rel="noopener noreferrer" target="_blank">the people around you</a>. An observational <a href="https://pmc.ncbi.nlm.nih.gov/articles/PMC11962463/" rel="noopener noreferrer" target="_blank">study</a> measuring motivation in healthy adults suggests motivational variability may reflect shifts in reward sensitivity — how strongly the brain weighs potential rewards against the effort required. <a href="https://pmc.ncbi.nlm.nih.gov/articles/PMC11962463/" rel="noopener noreferrer" target="_blank">Neuroscience research</a> suggests the brain is constantly running cost-benefit calculations. The ventral striatum — a key part of the brain’s reward system — activates when we anticipate something desirable. Another part, the anterior cingulate cortex, helps estimate how much effort a task will require and whether the reward is worth pursuing. When motivation dips, the calculation tips against you.Repetition gradually reduces the need for that calculation. Each time you perform a behavior, circuits in the brain’s reward and learning systems — particularly within the <a href="https://pmc.ncbi.nlm.nih.gov/articles/PMC7183880/#S6" rel="noopener noreferrer" target="_blank">ventral striatum</a> — strengthen their connections, reinforcing the circuits that link cues to action. Do something enough times and the behavior becomes more automatic.<h2>Never Miss Two Days in a Row</h2>“The single best rule for habit formation that I found is never miss two days in a row,” says Williamson. “So if you're quitting something or starting something, if you did the thing you're not supposed to do yesterday, you have to do it today.”Many people operate according to an unspoken convention: Miss one day and the habit feels broken. Research says otherwise. A <a href="https://onlinelibrary.wiley.com/doi/abs/10.1002/ejsp.674" rel="noopener noreferrer" target="_blank">study</a> following 96 people building simple daily habits over 12 weeks found that habit strength increased gradually with repetition — and that missing a single day didn't meaningfully disrupt the process.A separate <a href="https://pmc.ncbi.nlm.nih.gov/articles/PMC7135855/#S4" rel="noopener noreferrer" target="_blank">study</a> tracking people over 110 days found that habit strength increased steadily, with the steepest gains in the first few weeks. People who were more consistent during that window showed stronger habit formation overall, regardless of their baseline self-control. The beginning is when you can least afford to let a miss become two.That's what Williamson's rule protects against. "It stops this all-or-nothing purist mentality that I think causes people to feel defeated: If it's not perfect, or they haven't done it perfectly, there's no point doing it at all, which is not what we're aiming for," says Williamson.The rule also has a practical upside: It gives you somewhere to put a bad day. Forgot your water bottle rushing out the door? Pack it in your bag tonight and move on. Ordered takeout after a chaotic work day? Back in the kitchen tomorrow evening.<h2>Stack Your Habits</h2>If you have to make a conscious decision to follow your habit each day, you might opt out. Habit stacking — linking a new behavior to one you already do — removes that decision. It works because the <a href="https://www.cell.com/trends/cognitive-sciences/fulltext/S1364-6613(24)00266-3" rel="noopener noreferrer" target="_blank">brain tends to combine actions</a> and respond to contextual cues: Your environment, the time of day, and what you just did influence habits in ways willpower alone can’t, according to a <a href="https://pubmed.ncbi.nlm.nih.gov/34283681/" rel="noopener noreferrer" target="_blank">2022 review</a>. Start with something you already do on autopilot and attach the habit you're trying to build onto it:<ul><li>To stop doomscrolling before bed, put your phone on the charger in another room immediately after brushing your teeth.</li><li>To make getting morning sunlight non-negotiable, put shoes next to your bed and step outside for a 5-minute walk immediately after you get dressed.</li><li>To dial in mid-workout hydration, keep your electrolyte bottle next to your weights and take a few sips every time you re-rack a set.</li></ul>Habit stacks can be as long as your routine allows. “If you've got the luxury of being free enough on a morning to be able to do this, you can stack like five things back to back,” says Williamson. “You can get up and walk and journal and meditate and breath work and stretch and read.” The same logic applies at night, during a lunch break, or in the quiet minutes waiting in the school pick-up line.<h2>Repeat Until It Feels Automatic</h2>In the beginning, every new habit requires overcoming friction — especially if you're someone who likes to optimize. It's tempting to keep adjusting the routine instead of repeating it long enough to stick.But gradually, friction fades. What once required reminders and effort starts happening with less thought. Eventually the behavior feels like part of your normal routine — and skipping it feels slightly off, because it's just what you do.Often, the process feels so smooth a little helpful obsession builds, says Williamson. “If you have an obsession with the gym or building a business and you can't not think about this thing, I think this is the freest motivation and discipline you're ever gonna get.”That intensity doesn't last forever — but it doesn't need to. Once the behavior is wired in, it no longer requires the same effort, decision-making, or drive. “I go to the gym because I was obsessed with the gym for most of my twenties, and now I don't even use discipline and motivation,” says Williamson. One thing that accelerates that process: Choose habits that matter to you. A <a href="https://www.frontiersin.org/journals/psychology/articles/10.3389/fpsyg.2019.01504/full#h5" rel="noopener noreferrer" target="_blank">pair of studies</a> suggest behaviors aligned with your core values are more likely to become strong habits. Some researchers describe this as the integrated self — the degree to which your cognitive, emotional, motivational, and behavioral systems are working in concert. When a habit aligns with your values, it gets absorbed into that system and reinforces how you see yourself. That's what makes it stick.At that point, the habit isn’t something you're trying to maintain. It’s just part of how you live.FAQsQ: How are habits formed?A: Habits form <a href="https://pmc.ncbi.nlm.nih.gov/articles/PMC11962463/" rel="noopener noreferrer" target="_blank">through repetition</a>. Each time you perform a behavior, neurons in a part of the brain's reward system called the ventral striatum — specifically cells called spiny projection neurons — strengthen their connections. Over time, this reinforces the circuits that link environmental cues to automatic action.Q: What’s the best way to form a new habit?A: Three principles tend to support habit formation. First, commit to a 90-day window — <a href="https://onlinelibrary.wiley.com/doi/abs/10.1002/ejsp.674" rel="noopener noreferrer" target="_blank">long enough for most behaviors to become automatic</a>. Second, never miss two days in a row. <a href="https://onlinelibrary.wiley.com/doi/abs/10.1002/ejsp.674" rel="noopener noreferrer" target="_blank">Research</a> following people building daily habits over 12 weeks found that missing a single day didn't meaningfully disrupt the process. Letting one miss become two is where routines can start to unravel. Third, attach the new behavior to something you already do automatically. <a href="https://pubmed.ncbi.nlm.nih.gov/34283681/" rel="noopener noreferrer" target="_blank">A 2022 review</a> found that environmental cues — time of day, location, and preceding actions — influence habit formation in ways that willpower alone can't replicate.