To be used with foresight
Retractable leashes are useful when walking in areas where dogs have to be leashed, or if your dog doesn't always come when called. However, retractable leashes must be used sensibly and the following advice should be observed for their safe use.
Purchase the best quality retractable leash you can afford. Typically the tape ones are stronger than the cord variety. Make sure to choose the correct size for the weight of your dog, otherwise it may break when your dog suddenly pulls forward.
It is advisable to always carry a normal leash as well as the retractable leash.
A retractable leash should never be clipped to the collar as the pulling causes an enormous pressure on your dog's throat and neck. A length of only 2-3 meters (6-10 feet) can damage the discs of the neck, the throat and the thyroid glands when the dog jerks forward or constantly pulls. And the longer the leash is pulled out, the stronger the pressure on the throat and neck gets. When using the retractable leash, the dog should always carry a harness which will evenly distribute the pressure over a greater part of the body. The harness should be purchased in a speciality shop as it is essential that it fits the dog's body and cannot shift.
Don't expect to teach your dog to stop pulling whilst using the retractable leash. Your dog enjoys pulling ahead and wandering off. A retractable leash should not be used with a gentle leader or other training tools. The point of those tools is generally to teach your dog not to pull. If you want to teach your dog not to pull, you put a collar on him next to the harness. So when training to walk on a loose leash you clip the normal leash to the collar and when he is allowed to pull freely, you attach the retractable leash to the harness. The dog will quickly learn whether the pressure is on his chest or on his neck.
A retractable leash is suitable for a young dog that doesn't always react when called. A length of 5-8 meters (16-26 feet) gives your dog enough freedom to investigate the surroundings and walk at his own speed, while you can train the recall under controlled conditions.
Always keep the dog on a short, locked leash when meeting people or other dogs as the friction from the moving tape or cord can cause serious injuries when tangled around the legs or another dog's body. When meeting other dogs, especially when they are off leash, it is better to unleash your own dog - or at least replace the retractable with the normal leash to avoid that the dogs get tangled in the leash. With a normal leash you can let go if the situation is getting out of hand, whereas the retractable leash with its bulky handle can make things worse.
For trips to town retractable leashes are not suitable unless you kepp them short and locked so that the dog on his long leash doesn't get in the way of pedestrains.
When walking on or along a trafficked street, the dog should always be on a short and locked leash, or even better on a normal leash. You may not react quickly enough if the dog suddenly discovers something interesting and pulls out into the street.
Don't ever try to stop your dog by gripping the tape/cord with your hands. People have suffered serious injuries, including finger amputations and bad burns from retractable leashes.
It is a good idea to teach your dog to return the same way when he goes in among bushes and trees as this will save you from crawling around the vegetation when trying to untangle several meters/feet of leash.
Be aware that those bulky handles are easily yanked out of your hand if your dog hits the end of the line at full speed. If you drop it, your dog can get frightened when the leash retracts and he is hit by the handle and he may run off, getting even more terrified when "chased" by the handle bouncing behind him, making a horrible scraping sound on the pavement.