Begin with two real weeks
List the settings that appear in a typical fortnight: work, home, commuting, exercise, evenings, care responsibilities, and travel. Add the weather and the actual time between laundry days.
This keeps the capsule connected to your life. A formal office, a bicycle commute, and a work-from-home routine require different balances even when the total number of pieces is similar.
Choose outfit formulas before quantities
Write three to five combinations you already enjoy, such as shirt plus relaxed trousers plus loafers or knit plus skirt plus boots. Count how many versions you need to repeat those formulas comfortably.
Aim for compatibility within small groups rather than forcing every item to match every other item. A capsule can contain color, pattern, and personality without becoming difficult to combine.
Test before adding anything
Create at least ten complete outfits from the proposed capsule, including the hardest days in your schedule. Notice whether one shoe, layer, or bottom carries too much of the plan.
Wear the capsule for two weeks and record what you choose. Items that remain untouched provide better information than an idealized checklist, while frequent repeats reveal where an extra option may be useful.