Professor Katy Milkman from Wharton conducted a large scale field experiment in 2017-18 in collaboration with 24 Hour Fitness, a gym chain in the US. It involved over 2500 participants across multiple locations.
The experiment focused on the question:
Strict schedules or flexible routines: What builds lasting habits?
🔬 Participants were randomized into two groups, each encouraged to form an exercise habit over a 28-day period:
🔹 Group 1 – The Strict Schedulers:
They were asked to pick a specific time of day to work out—say, 7:00 am every morning. They got reminders and encouraged to stick to the exact time.
🔹 Group 2 – The Flexible Planners:
They were also encouraged to pick a time—but were told they could move it around and go anytime that suited them, as long as they kept going.
Here’s what happened.
📈 In the first few weeks, the strict group outperformed. Their attendance was higher. The structure helped them get started.
But over time, real life crept in—meetings ran late, family emergencies came up, energy dipped or travel plans changed. Many couldn’t stick to the rigid routine.
💡 The flexible group? They adapted.
If they missed a morning slot, they made it in the evening. If a weekday got busy, they went on Saturday. Their numbers weren’t dramatic—but they stuck with it longer.
When the incentives were removed and the experiment ended, the flexible planners continued working out more regularly than the strict ones.
So, what does this teach us?
✅ Structure helps you start a habit.
But
✅ Flexibility may help you keep a habit.
So, true habit may not be about building rigid perfection, but adaptable consistency.
I could personally relate to this – if I miss going for my walk one day, I compensate in the weekend. If I miss my meditation in the morning as I overslept, I do it in the evening.
Has flexibility helped you stick to a habit? Would love to hear your experience.
Perspectives 