Harnesses and collars both provide means for attaching ID tags, but their effectiveness varies. Collars are advantageous for continuous wear, allowing ID tags to remain on the dog at all times, which is crucial for identification if the dog gets lost. However, collars can pose a risk for dogs that pull vigorously, potentially leading to neck injuries. On the other hand, harnesses, which are better for controlling dogs and reducing neck strain, are not typically worn all day. This means ID tags attached to harnesses might not be on the dog at all times, reducing their effectiveness in case the dog escapes while not wearing the harness.