[MichaelGG]

Short variable names are fine with context. "cs : Customer list" - we know it's a list of customers from the type, no need to repeat. And a loop on it could easily be "for c in cs". Single letters are also useful in local or anonymous functions.

Reuse identifiers? Yes! If I've got a parameter foo that's a string, then I convert it into an int and never use the string again, why not rebind the identifier? It makes it clear the old foo is no longer in use, and prevents such use.