That's a really great rule of thumb. I think I might use that. x::xs might not be so nice if the body of the match has twenty lines in it, especially if y::ys a

That's a really great rule of thumb. I think I might use that. x::xs might not be so nice if the body of the match has twenty lines in it, especially if y::ys also exists. That'd be the pseudo-equivalent of saying, "Joe and Sam were getting food and he wanted a burger but he wanted steak so he finally argued that they should go to Bob's Grill which had both and he agreed." (Not really, because the sentence is actually totally ambiguous whereas with variables it just involves an extra lookup for the reader.) But if the body is one or two lines, there's not much purpose in the extra characters.