1. Plan combinations, not seven costumes
Choose a small colour family and build several outfits around two or three bottoms, a few tops, one warm layer, and versatile sleepwear. Underwear and socks are the categories that usually require a day-by-day count. The exact mix depends on weather, laundry access, and the purpose of the trip.
2. Use the destination forecast carefully
Check the forecast close to departure, then prepare for a reasonable range rather than every possibility. A compact layer is often more useful than a second heavy item. If formal clothing is required, let it earn its space by working in more than one outfit.
3. Finish with a removal pass
Once packed, remove one item from each category and see whether the combinations still work. Leave room for toiletries, souvenirs, or a change in plans. A carry-on that closes comfortably is better than one that only works after a wrestling match.
The short version
Choose for your real route, test the decision before departure, and verify changing airline or product details from authoritative current sources.