Using the "using..." Statement reduces the verbosity of code in .NET. However, does it affect performance if you're issueing a "using..." Statement to include a namespace you'll never use?

Say for example:

using System;
using System.Data;
using System.Data.SqlClient;
using System.Data.OleDbClient;

...

In this case you'll always use the SqlClient but do you get a performance hit for including OleDbClient if you never use it?

Should I be cautious about what namespaces I include? More importantly should I be cautious about how I group my custom classes in certain namespaces?

TIA