Generally speaking, most kits are designed to last about 3-5 days. Many of the products out there on the market that claim they would last for 5 days wouldn’t really last that long according to many past users. It’s always important, especially in the face of an emergency situation, to err on the side of caution. Even though a pack might claim that ti can last up to 5 days, it would be wise to assume that it will last about 72 hours.