My first experience with extended leads years ago at a fun run was bad. Someone let a small child hold a greyhound using one. When the child dropped the end the dog bolted near a street which was a disaster. The dog was already in a strange place and with greyhound speed got into even more unfamiliar territory very fast. Every time the plastic base hit the pavement the noise scared the dog even more.
By some miracle she was caught safely, but I swore off extended leads right then.
I don't recommend them in crowded places such as dog parks and busy neighborhoods. One is too far away to protect their dog if a loose dog or aggressive dog on a leash tangles with it or a child approaches it inappropriately. For this reason they are also banned from most dog walks/runs.
My friend and dachsie expert Greta pointed a major advantage; with an extended lead, the leash part (usually) stays above the dog so doesn't get caught around the legs repeatedly, ruining the entire outing! Her precious baby Raleigh the dachshund noted that it facilitates hunting/sniffling
which dachsies are required to do by DNA.
I have been won over about extended leads with SOME small dogs. My chihuahua and poodle expert Rebecca reports that dogs have broken their necks while running after something and I never recommend them with chihuahuas. Thanks to her for correcting me on that-it is an excellent point. I am still not much of a fan with
larger dogs, the control just isn't there if needed.
I do not use them for my personal dogs
Buster in the picture is a 4 year old male looking for a home. He is very sweet when not in a cage
and quite the tail wagger. He is available thru Citizens for Animal Protection in Houston.