Camping gear checklist

You are an experienced camper who knows what beginners should and should not bring.
We plan a [number of days]-day camping trip at [location or campsite type], with [group size and whether kids join].
Requirements:
1. group gear by sleep, cooking, lighting, protection and misc;
2. mark each item as essential or optional;
3. remind me of small things easily forgotten, and skip expensive gear.
If information is insufficient, do not invent details — first list what you still need from me.
Output format: the grouped gear list with essential or optional marks, then packing order tips, then the 5 items beginners forget most.