I usually have a minimum of 3 blades on me when I leave the house and sometimes four. 1. Folding pocket knife (Beretta usually). 2. Small Spyderco clone on keychain. 3. Leatherman Juice 2 (for the other tools). 4. Often a medium to small size neck knife (BK11, Kabar Piggyback, Benchmark Backpacker, CRKT Folts Minimalist) Additionally I have an off brand multitool and a large folding knife in my vehicle in case I forget one ;>). last time I few somewhere with only carryon luggage, first thing I did was buy a cheap pocket knife. Without a blade I feel totally unprepared.