My teacher ve always said that we shouldn't write the same part of code more than once while programming. But should a code which priority is to be robust & **quick** use class and methods instead of write down the same code ever and ever?! Does calling a class take a little bit more of time than a direct code?!

For example if i want to do that:

```
Program1.Action1();
Program1.Action2();
Program1.Action3();
& 
Program2.Action1(); 

```

etc etc etc

and I want these actions to be perform the quickest as possible, May I call actions() or write down the full code?!

Adnt his question lead to an another one: 
For a a project we need to make it easily readable by the teacher so we have a lot of "class tab" on visual studio, we make everything public and we call our class or methods in our mainform.

Ok it's quite organized, very easy to read, BUT doesn't make the code slow down?!
Does public "class tab" are slower than a private class in our mainform?! 
I didn't find anything conlusive anywhere.. Thank you.