Start with the actual days
Count the number of full days, travel days, and any special moments that need a different outfit. This keeps the bag connected to the trip instead of imagined emergencies.
Pack around comfort first
Shoes, layers, chargers, and small personal essentials usually matter more than extra options. A lighter bag still needs to support the way you travel.
Use a small maybe pile
Place optional items in one small pile. If the pile does not fit naturally, remove one or two things before closing the bag.