My favorite use case for the Fibonacci sequence:

My favorite use case for the Fibonacci sequence:
Estimating the complexity of tasks.

(Stolen from Scrum. Still gold.)

1, 2, 3, 5, 8, 13, 21

Here’s how I think about it:
• 1–3: Clear. You know what to do - GSD
• 5–8: Fuzzy. There are unknowns - expect delays (or find more expertise)
• 13–21: 🚨 Too big. Break it down.

Sending a Slack message: 1
Writing an investor email: 2, 3, or 5
Launching a new product: 21

Time is hard to estimate.
Complexity? Easier — and way more useful.

Why skip numbers?
Humans are bad at estimating... and get worse over larger tasks and longer timelines.

The more you practice, the better your internal compass gets.
Struggling to move faster and with less chaos?

Like pausing to top off your car's gas tank before a road trip, a pitstop to evaluate complexity is worth the effort.

PS. It's particularly helpful for managers to coach, even if they don't fully understand the context.