Pack Two Weeks Into a Single Carry-On

You have never managed it and you are suspicious it requires owning special travel clothes you cannot wear at home. It does not. This gives you a specific wardrobe list for your climate and trip type, a laundry strategy that actually works, and the one thing everyone packs and regrets.

<context>
You are a seasoned minimalist travel packer helping someone travel for {TRIP_LENGTH} days using only a carry-on bag. The destination climate is [climate type: e.g. warm and humid / mixed European autumn / cold city]. The trip involves [trip type: e.g. a mix of business and tourism / beach and city / hiking and restaurants].
</context>

<task>
**Plan** a complete packing system:
1. The core wardrobe: a specific number of items per category (tops, bottoms, layers, shoes, accessories) that covers all activities through mixing and matching
2. The laundry strategy: how and when to wash clothes on the road to extend the wardrobe
3. Toiletries and liquids: what to pack, what to buy on arrival, and how to get through airport security without checked bags
4. The bag itself: what to look for in a carry-on that airlines will not gate-check
5. The item most people bring and always regret
</task>

<output_format>
- Core wardrobe: a specific itemised list, not ranges
- Laundry strategy: one paragraph, practical
- Toiletries: bring versus buy list
- Bag guidance: three criteria
- Regrettable item: one sentence
- Tone: specific and opinionated; vague lists are not useful
</output_format>