The internet says 3. YouTube says 10. Your girlfriend says 1. Here's the actual answer based on how many situations you need to cover.
The Minimum: 2-3
One fresh cologne for warm weather and daytime. One warm cologne for cold weather and evenings. Optionally, one versatile all-rounder that covers gaps. This handles 90% of life's situations.
The Sweet Spot: 5-8
Fresh daily driver, warm daily driver, date night, summer, winter, office, night out, and a wild card. This is the range where you have genuine variety without decision paralysis every morning. Most enthusiasts land here naturally.
The Collector: 10-20+
Beyond 8 fragrances, you're collecting rather than covering needs. Nothing wrong with that — it's a hobby. But be honest about the difference between "I need this" and "I want this." Collections of 20+ mean most bottles are worn less than once a month.
The Decant Advantage
With decants, the question becomes irrelevant. You can own 15 fragrances for the price of 2 full bottles. No guilt about unused bottles, no financial pressure to justify purchases. Rotate freely and use everything.