Having a rope along for the scrambly day hikes is a good thing. Beyond that, I suggest that day hikers carry the 10 essentials, per the Seattle Mountaineers:
It is good to have a cell phone or two along.
- Navigation: Whatever it takes to find your way back if you are separated from the group.
- Sun Protection: Includes hat,
sunscreen, sun glasses, etc.
- Insulation: Basically extra clothing. Your insulation should allow you to survive
the worst conditions that can be realistically expected.
- Illumination: Whatever light you need if you are delayed and must travel after dark.
- First Aid Supplies
- Fire: Matches or lighters
- Repair Kit and Tools: Knife or multitool. And duct tape, perhaps wrapped around your poles.
- Nutrition: Something you won't normally eat, to hold in reserve.
- Hydration: Enough water for the day. Purification will help in a pinch.
- Emergency Shelter: To keep you warm if you are stuck overnight - space blanket or an extra-large plastic trash bag
And bicyclists need spare tubes and tools.