In my experience, it depends on the bag. There are good and bad pre-made bags. Some are packed with better items than others—although I firmly believe any survival or first aid kit can always be improved. Sometimes it’s as simple as adding some extra bandages. Other times it may call for an entirely different water filtration system. The key is to inspect the contents of the bag ahead of time to determine what to keep in it, and what to replace with something better.