After every fight I wipe the steel clean with a damp rag, then let it air dry, oil it in the morning and in the evening, and run a whetstone along every edge until the edge feels like a whisper. I keep a small stone in my pocket and a single prayer to the old gods before I start sharpening, as a reminder that a blade is only as good as the oath it carries. If you follow that, the blade will stay as sharp as the memory of a lost duel.