Is it worth removing "using System" from my files?

Question

Developing a series of POCOs on my project, and just realized that some of them doesn't need the using System; clause.

Is there any performance or size penalty for leaving unused using <module>; on my objects or project ?

Will my classes get bigger, or slower, or bloated because of this or the compiler/optimizer is smart enough to take care of this?

Answer 1

no there are not performance issue .

it is just a readability matter(I would suggest to remove them)

more info at: Why should you remove unnecessary C# using directives?

Answer 2

All the "using System;" statement does is allow you to use that namespace without fully qualified names. It doesn't affect run-time performance in any way.