1. Better control: A dog harness can provide better control over your dog's movements, as it distributes the pressure from pulling across the dog's chest and back rather than just their neck. This can be particularly useful for dogs that pull a lot, as it reduces the risk of injury to their neck and spine.
2. Prevents choking: Unlike collars and leashes, which can put pressure on a dog's throat and windpipe, a harness won't choke your dog if they pull or lunge.
3. Comfort: Harnesses can be more comfortable for some dogs, as they don't put pressure on the dog's neck or restrict their breathing in any way. This is particularly important for dogs with respiratory problems or breeds with flat faces, such as Pugs or Bulldogs.
4. Safety: A harness can also provide an extra layer of safety as it is much for difficult for your dog to slip out of a harness.

It is important to ensure that your dog's harness is properly sized for their body. The harness should fit snugly without causing any discomfort to your dog. You should be able to fit two fingers between the harness and your dog's body. Also, check that the harness is not causing any skin bunching or indentations. If you notice any discomfort, try resizing the harness, switch to a different style or consider using a collar instead.

1. Better control: A harness can give you better control over your dog during the hike, as it distributes the pressure from pulling across the dog's chest and back. This can be particularly important when hiking on uneven terrain or steep inclines, as it helps prevent your dog from pulling you off balance.
2. Increased comfort: A well-fitted harness can be more comfortable for your dog than a collar, especially during long hikes. A harness can distribute weight more evenly across your dog's body, reducing pressure on their neck and throat. This can be particularly important for dogs with respiratory issues or those prone to pulling.
3. Safety: A harness can provide an extra layer of safety during the hike. If your dog slips their collar or leash, they will still be attached to you by the harness. Additionally, many harnesses have reflective strips or other features that increase visibility in low-light conditions.
4. Support: Some harnesses are designed with additional features that can provide support for your dog during the hike. For example, a backpack-style harness may have a handle or straps that allow you to help your dog over obstacles or provide support if they become tired.