2-3 days. Reiki is a kind of safe, protective, natural and harmonious cosmic energy, and it is best to do it every 2 to 3 days. Reiki therapy is an ancient energy therapy rediscovered by Japanese master Aoi sora. Some western medical professionals also use reiki therapy to help patients with cancer and serious diseases, because it can enhance patients' thinking and immune system, effectively avoid or prevent the invasion of sick gas, and has a complementary role with traditional medical care.