My favorite leashes are leather and they are 6' long. And thats what I use the most often too.
I do have quite a few nylon leads, all 6' as well. I keep a few spares in my car & at home. They do get used sometimes but not often. Just depends on if I forget a leather one, or if I know its going to get really muddy or the like I'll use a nylon one, etc...
I do have 2 short (maybe 1' ) leather leads but they are only used for certain training sessions.


I do have flexis, I love & hate them. lol I ONLY use them if like I go hiking with no other dogs or at least no other leashed dogs in places that are not crowded. I'll NEVER use them if there are a lot of people &/or pets &/or objects around.