For most outdoor activities, having a first aid kit around is quite important as all outdoor activities are run with the risk of injuries. Hence having a well equipped first aid kit together with a competent first aider would be useful should something go wrong.

When deciding on what items to pack into a first aid kit, the best way to make choices is to run down what are the possible injuries that could occur and what items would be useful in treating a victim when they do occur. For example, say you are going for a night hike and you determine that a sprain or muscle stretch is quite possible. You would then need to think, what are the possible first aid items for this problem. First aid items like cold spray or ice pack, torch light and roller bandage are useful and as such, should be packed into the kit. Conversely, things that would not help treat possible injury should not be packed inside. They would just be extra weight as they serves no purpose.

Once you determine what needs to be brought along, you would next need to ensure that your kit is able to serve the number of people going. For example, if you yourself were going for a hike, 3 plasters would be enough to meet your needs. But if 30 people were going for a hike, would 3 plasters be sufficient? So pack quantity based on the quantity that will be served by the kit.

Lastly, it is important that the person using the kit knows where all the items in the kit are located. In an emergency or in the dark, finding what you want quickly is important. Also what a first aider would want is to know exactly what is in the kit. He would be best able to treat the victim with what is on hand if he knows what he has.

There is no 'one-size fits all' solution for packing a first aid kit and everyone will have a different view of what needs to be brought along, even for the same activity. So its fine to pack in whatever you want to work with as long as you are comfortable in using what you bring.