German Surplus Sewing Kit w/ OD Pouch

Buy a sewing kit.  Keep it with you in the field.  Your gear will tear, it will rip.  And if you don't have a means to fix that, and the practice to do so -- you're hosed.  

Repairing your kit is way cheaper than buying a replacement.  Don't be mad at me for pointing out the obvious, you know this is good for you.