Leash and harness choice affects both control and a dog's physical comfort in ways that go beyond simple preference.
Harness vs. collar for dogs that pull
A collar puts pressure directly on the neck and throat when a dog pulls, which can strain the trachea and neck over repeated pulling, particularly in smaller breeds or dogs with pre-existing neck sensitivity. A well-fitted harness distributes that pressure across the chest and shoulders instead, generally considered gentler for a dog that pulls regularly on leash. A collar remains useful and appropriate for holding ID tags and for dogs that walk calmly on leash without much pulling — the concern is specifically about a collar bearing the full force of a dog pulling hard against it repeatedly.
Front-clip vs. back-clip harnesses
A back-clip harness (leash attaches at the shoulders) is comfortable and simple, well suited to dogs that don't pull much. A front-clip harness (leash attaches at the chest) gives a handler more leverage to redirect a dog that pulls, since pulling forward tends to turn the dog slightly sideways rather than letting them pull straight ahead with full force — often recommended specifically as a training aid for dogs still learning not to pull.
Retractable leashes carry real, documented risks
Retractable leashes allow more roaming range, but the thin cord can cause rope burns or lacerations to human skin if it wraps around a leg or hand, and the mechanism gives a handler less immediate control to react quickly compared to a fixed-length leash — a meaningful concern for a dog that might unexpectedly bolt toward traffic or another animal. Many trainers and veterinarians recommend a standard fixed-length leash for walks in areas with any real hazards (traffic, other dogs, crowds), reserving a retractable leash for open, controlled spaces where the reduced immediate control matters less.
Material affects durability and grip
Nylon is affordable, widely available, and comes in many widths and styles, but can degrade faster with heavy outdoor use and sun exposure. Leather is more durable over time and can feel more comfortable to hold for long walks, but costs more upfront and needs some care to avoid drying out or cracking. Both are reasonable choices — the difference is mainly about longevity and feel rather than one being categorically better.
The one thing people forget
Check the harness fit periodically, not just at the time of purchase — a growing puppy or a dog whose weight changes over time can outgrow or loosen out of a harness that fit correctly when first bought. A harness that's become too loose can allow a dog to back out of it entirely, especially if startled, which defeats the point of using one in the first place.