Although I never check my backpack when traveling to the Camino, I almost always check it coming home. The last time we checked our knives and poles in a separate equipment bag, it didn’t arrive in SdC when we did. As we were immediately leaving for Ferrol, that was a minor problem, but one that was easily addressed at an outfitters shop. At least we had our packs! I now buy a knife and poles in France or Spain upon arrival. As I am less concerned about my pack arriving with me on the same plane returning home, I check it so that it carries knives, corkscrews, poles, etc. I also carefully pack a bottle or two of my favorite vermouth from Madrid. Although my pack upon return has been delayed or misplaced, it has never been lost and usually shows up at my house within a day or two. So, rather than mail things home, check your pack with the airline with the items that you can’t bring in the cabin.