How to build good habits that stick

How long does it take to form a habit?

Often longer than the 21 days you may have heard, and it varies a lot from person to person. The best-known study is by Phillippa Lally and colleagues at University College London, published in 2010 in the European Journal of Social Psychology.

They asked 96 volunteers to pick one eating, drinking or activity habit, such as drinking a bottle of water with lunch, and do it daily after the same cue for 12 weeks. Each day, people rated how automatic the habit felt. For the 39 people whose results fitted the researchers' model well, the middle figure for the habit to get close to as automatic as it was going to get for them was 66 days. The range was 18 to 254 days.

A few honest caveats. The volunteers were recruited at a university, so they're not everyone. The study ran for 84 days, so the longest times were estimates of where each person's curve was heading, not days anyone actually counted. And in their discussion, the authors note that roughly half the people didn't do their habit consistently enough for it to become a habit at all, even though they'd volunteered to try. The exercise habits took about one and a half times longer than the eating and drinking ones, though the study wasn't large enough to be sure of that difference.

What this means for you: expect weeks or months, not days. Simple habits may settle faster than complex ones. And if it still feels like effort at day 30, nothing is wrong with you. You're on the curve.

How to build a good habit, step by step

You don't need a new morning routine or a total life overhaul. You need one small action, tied to a moment you already meet every day, and somewhere to notice that you did it.

1. 1Choose one habit. Pick the one that would make the biggest difference to your week, and leave the others for later.
2. 2Make it small. Shrink it until you could do it on your worst day: two pages, not a chapter; shoes on and out the door, not a 5k.
3. 3Tie it to a cue you already have. Pick something you do every day without fail, such as making coffee, brushing your teeth or sitting down on the train.
4. 4Write it as a plan: 'After I [cue], I will [tiny habit].' For example, 'After I pour my morning coffee, I'll write one line in my journal.'
5. 5Keep the place and time the same. The more the situation repeats, the more it can start to prompt the action for you.
6. 6Make it easy to start. Put the book on your pillow, the trainers by the door, the water bottle on your desk.
7. 7Notice each time you do it. A tick on a paper tracker is enough.
8. 8If you miss a day, start again at the next cue. One miss doesn't reset anything.

Steps 3 and 4 have some of the strongest evidence. Psychologist Peter Gollwitzer calls these if-then plans 'implementation intentions'. In a 1999 paper in American Psychologist, he set out how deciding in advance 'when this happens, I'll do that' lets the moment itself prompt the action, so you don't have to rely on remembering or feeling motivated. A 2006 review by Gollwitzer and Paschal Sheeran pooled 94 independent tests and found a medium-to-large effect of these plans on reaching goals.

Here's what that can look like. Say you want to read more. Instead of 'read every night', you decide: 'After I plug my phone in to charge, I'll read two pages in bed.' You leave the book on your pillow. Some nights you read twenty pages, some nights two. Both count. After a few weeks, plugging in your phone starts to feel like the start of reading time.

The free tracker below helps you set up one to three habits like this, with a cue, a tiny version and a simple month-long grid to tick.

What is habit stacking?

Habit stacking means attaching a new habit to one you already have, so the old one becomes the cue: 'After I brush my teeth, I'll floss one tooth.' It's the same idea as step 4 above. Writer James Clear popularised the name in his book Atomic Habits, and he credits behaviour scientist BJ Fogg, who calls it anchoring in his Tiny Habits method.

It fits what habit research finds. Wood and Rünger's review describes studies that used tooth brushing as the cue to help people build a flossing habit. The trick is choosing an anchor that really does happen every day, at a fairly fixed time and place. 'After I check my email' is a weak anchor if you check it forty times a day. 'After I sit down at my desk in the morning' is a strong one.

If you'd like to read Atomic Habits, it's a clear, practical book. It's worth knowing that Clear is a writer rather than a researcher: the core ideas fit habit research, but the book pulls ideas together rather than adding new evidence. There's more on it in the guide to the best self-growth books.

Should you track your habits?

Tracking can help, as long as it stays a tool for noticing rather than a stick to beat yourself with. A 2016 meta-analysis (a study that pools many studies) by Harkin and colleagues looked at 138 experiments on monitoring progress towards a goal. People who were helped to monitor their progress were more likely to reach their goals, and the effect was larger when progress was physically recorded, for example written down.

A paper tracker is about as simple as recording gets. One tick a day, in the same spot, takes seconds. It also shows you patterns you'd otherwise miss: the habit that only happens on weekdays, or the week everything slipped because you were ill.

Two cautions. First, phone reminders may not be the shortcut they seem: one study described in Wood and Rünger's review found that electronic reminders increased how often people did the habit but got in the way of it becoming automatic, perhaps because a reminder keeps you deciding instead of letting the situation do the prompting. Second, if a gap in your tracker makes you feel like a failure, change how you use it. A tracker is a record of what happened, not a verdict on you.

The free printable habit tracker has room for up to five habits over a month, a cue and a tiny version for each, and a short review at the end of the month.

What happens if you miss a day?

Not much, if you pick it up again. In Lally's study, missing one opportunity to do the habit did not materially affect how the habit formed. The habit felt very slightly less automatic after a missed day, then carried on climbing once people did it again.

The authors did note a different picture from an earlier study, where missing a whole week made people less likely to keep going. So the useful rule isn't 'never miss'. It's 'come back at the next cue'. If you miss a day, do the tiny version next time, without trying to make up for lost days.

If you notice yourself thinking 'I've ruined it, what's the point', that's the all-or-nothing voice, not the evidence. The guide to self-compassion has ways to answer it more kindly.

Signs a habit is starting to stick

There's no finish line, but you might notice some of these:

• You do it without having to decide to.
• The cue pulls you towards it: you sit at your desk and reach for the water bottle.
• Skipping it feels a bit odd, like leaving the house without your keys.
• It takes less effort on tired or busy days than it did at first.
• You sometimes realise you've done it without remembering starting.

These match what researchers mean by automaticity: an action that runs with little thought or effort once the situation sets it off.

Why is it so hard to build good habits?

If you've tried and stalled before, that's common, and it usually isn't a character flaw. A few common causes:

• The habit is too big. 'Go to the gym five times a week' needs a lot to go right. A tiny version survives a bad week.
• There's no clear cue. 'Sometime today' is never a specific moment, so the habit has nothing to attach to.
• You're relying on motivation. Motivation rises and falls. A cue and a plan carry you through the low days.
• The old cues are still there. If your phone is on the bedside table, scrolling will often win over reading.
• Life is stressful. Wood and Rünger's review describes research showing that stress makes people fall back on their existing habits, good or bad. A hard month isn't the time to judge whether you can change.
• You're trying to change everything at once. Each new habit needs its own repetitions. One or two at a time is plenty.

One hopeful point from the same review: life changes such as moving house or starting a new job can loosen old habits, because the old cues aren't around. If your life has just shifted, it may be a good moment to set up the habit you want.

Common mistakes when building habits

• Starting with the ideal version instead of the tiny one.
• Picking a cue that doesn't happen every day, or happens at random times.
• Tracking five new habits at once, then dropping them all together.
• Treating one missed day as proof it's not working.
• Choosing a habit because it looks good on someone else, not because it matters to you.
• Making the habit about a result you can't control ('lose weight') instead of an action you can ('walk after dinner').
• Waiting to feel ready. Feeling like it tends to come after you start, not before.

If your habit is part of a bigger goal, the goal-setting worksheet helps you turn the goal into a specific plan, and the self-growth plan helps you choose which area of life to start with. If it's the starting itself that keeps slipping, the guide to stopping procrastinating may help more.

When to get more support

Sometimes struggling with habits is about more than habits. If you can't get going with anything because you feel flat, hopeless or exhausted most days, that may be low mood or depression rather than a lack of discipline. If focus and follow-through have always been unusually hard for you, it might be worth asking about ADHD. And if the habit you want to change is drinking, drug use, gambling or eating in a way that feels out of control, that deserves proper support, not just a tracker.

A GP is a good first step and can talk you through options, including talking therapies. This guide is for self-reflection, not therapy or medical advice. If you ever have thoughts of harming yourself, please contact a crisis line straight away: Samaritans on 116 123 in the UK and Ireland, call or text 988 in the US, or find a free helpline where you live at findahelpline.com. You deserve real support, not just a checklist.