How long does it take to create a new habit? (2015)

Good vs bad habits and human nature

• Several comments note it’s far easier to fall into “bad” habits (overeating, substances) than build “good” ones.
• Evolutionary speculation: in environments of scarcity, “if it feels good, keep doing it” was adaptive; modern abundance turns those drives against us.
• Some argue that “good” vs “bad” is relative to context: carbs and grains both enabled civilization and modern obesity.

Ambiguity of the “21-day” claim

• Many readers initially assumed the title meant habits form in less than 21 days, then felt misled when the article says ~66 days on average, up to 254.
• Others read it as “not in just 21 days,” i.e., more than 21.
• Discussion touches on how marketing language, omitted qualifiers (“only,” “even”), and everyday phrasing bias interpretations.

Huge individual variation and anecdotes

• Stories range from smoking taking days to become addictive and years to fully shake, to diets that “click” instantly then later collapse with life changes.
• Some people feel a strong habit by ~3 weeks; others say 3 months for solidity, 3+ years for permanence, or even ~10 years for deep character change.
• A weight-loss anecdote: first three weeks felt hardest, then effort dropped sharply.

Identity, emotion, and neurodiversity

• A recurring theme: habits stick when integrated into identity (“I am a runner” vs “I’m trying to run”).
• Emotion-driven habits (comfort, relief) are reported as especially hard to change.
• People with ADHD and bipolar describe radically different experiences: some say routines barely form and vanish quickly; others find deliberate routine crucial for coping.

Mechanics: effort–reward, triggers, and habit stacking

• One model: habits depend on effort/reward ratio; strong rewards can wire habits quickly (including addictions).
• Tactics mentioned: shrinking behaviors (tiny habits), chaining new actions onto existing ones, and using clear triggers.
• A course framework: habits should be tangible, self-contained, done daily, tied to triggers, and often built in tiny steps (e.g., just picking up floss at first).

How quickly habits form—and vanish

• Multiple comments note that habits can stop in just a few missed days, even after years.
• High stakes (money, pain, scarcity of water) can make adoption nearly instant, as with gym-going for access to showers.

Diet, health, and environment

• Long subthread on “healthy breakfast” shows uncertainty in nutrition science but rough agreement on: fewer ultra-processed foods, more whole foods, and enough protein and fiber.
• Several emphasize environment over willpower: stock the right groceries and design surroundings so the “good” habit is the path of least resistance.

Culture, stakes, and “tough times”

• Some religious and cultural practices use ~40-day rituals, interpreted as deliberate habit-building periods.
• A side discussion explores whether hardship and high stakes forge stronger habits and character, versus the downsides of comfort and “babying” children.