The 3-3-3 packing rule is a minimalist travel formula: 3 tops, 3 bottoms, 3 pairs of shoes. Nine pieces total. Mixed correctly, they produce up to 27 different outfits.
The method was popularized by TikToker Rachel Spencer for a London trip. It draws from Project 333, a 2010 capsule wardrobe challenge by Courtney Carver that limited everyday wardrobes to 33 pieces for 3 months.
The 3-3-3 version works best for 4 to 7 day trips. For longer trips, the 5-4-3-2-1 method adds variety.
The trap is buying 9 random pieces. The formula only works when every piece coordinates in color, fabric weight, and formality.