Retractable leashes are popular primarily because they aren't as confining as regular leashes which allows dogs more freedom to sniff and poke around on walks but unfortunately these leashes aren't safe for the following 8 reasons:
1. The length of retractable leashes, some of which can extend up to 26 feet, allows dogs to get far enough away from their humans that a situation can quickly turn dangerous.
In the above scenario, or one in which your dog is being approached by an aggressive dog, it is nearly impossible to get control of the situation if the need arises. It's much easier to regain control of (or protect) a dog at the end of a six-foot standard flat leash than it is if he's 20 or so feet away at the end of a thin string.
3. The thin cord of a retractable leash can break – especially when a powerful dog is on the other end of it. Not only can that put the dog and whatever he may be chasing in danger, but also the cord can snap back and injure the human at the other end.
In addition, many people have been pulled right off their feet by a dog that reaches the end of the leash and keeps going. This can result in bruises, "road rash," broken bones, and worse.
5. Retractable leashes, like most retractable devices, have a tendency to malfunction over time, either refusing to extend or retract.
6. Dogs have also received terrible injuries as a result of the sudden jerk on their neck that occurs when they run out the leash, including neck wounds, lacerated tracheas, and injuries to the spine.
7. The handles of retractable leashes are bulky and cumbersome making it next to impossible to hold two in one hand when you need to reach into your pocket for that important phone call.
Also, the plastic handle is slippery and it gets even worse when it's raining because it will be very difficult to hang onto when a dog suddenly pulls at the leash.
8. As a professional dog walker of ten years I cringe when I see the above scenario because this dog is walking the owner rather than the other way around!
Many owners like to give their dogs the freedom to wander ahead but if a squirrel, a dog who is not well mannered, a bicyclist, etc, suddenly crosses the dog's path the chance to control the situation is difficult because the leash is too long to be pulled back quickly.
In my opinion, dogs MUST be walking beside or slightly behind the owner. Period.
If your dog is well trained enough to master a regular leash and a retractable leash by walking you without being confused you could be one of the rare guardians that can walk your pooch on any kind of leash without increasing risks to either one of you.