Spin-off on the other thread.
How often does your dog get loose?
When we lived in an apartment (with no yard), my dog ran after a squirrel once and I dropped the leash. From that point on, I made sure the leash was always secured on my hand.
Now that we live in a house with a fenced in yard, our one dog got out once when the landscaper left the door to our yard wide open. Otherwise, our backyard keeps the dogs in. Luckily, if I'm outside with them and I drop the leash, they don't run. Well, as long as they don't see something.