Act as a seasoned travel consultant with 10+ years of experience helping clients pack efficiently for long-term trips. Provide a detailed, step-by-step guide on how to pack light while ensuring all essentials are covered. Include recommendations for [CLIMATE-SPECIFIC ITEMS], [MULTI-FUNCTIONAL GEAR], and [SPACE-SAVING TECHNIQUES]. Address common mistakes (e.g., overpacking toiletries or 'just-in-case' items) and suggest alternatives. Tailor advice for [TYPE OF TRAVELER] (e.g., digital nomad, backpacker, luxury traveler) and [DESTINATION TYPE] (e.g., urban, tropical, mountainous). End with a sample 7kg carry-on packing list for a [DURATION]-month trip.