Optical sizes for logos?

[JamesM]

Most corporations I've done design work for don't have different versions for different sizes.

Multiple versions sounds good in theory, but it complicates things and creates the possibility that vendors or employees will use the wrong version.

Most employees can't even select the right fonts or colors, let alone pick the right logo version. And when working with an outside vendor they may send them the wrong logo version.

I'd agree there are occasional instances where it makes sense, but most professional logos are designed to look good large or small, and are scalable vector files.