Anything that can expire—medication or some antiseptic or sting treatments—should have an expiration date marked, and you should check them before any outing to re-stock if anything has passed its date. But other items—tools, bandages, gauze, etcetera—naturally don’t expire. Just be sure they’re not damaged and in good operating condition before departing. Schauf recommends going through your kit and replacing perishables every few years.