Question: we know that view state is easily get abused, but asp.net webform are heavily depending on this feature.

I want to know whether you disable viewstate by default, and ONLY add it wehn it's needed. Or you take the visual studio default, which actually enables viewstate by default.

Answer: 
As others have said, unless we are talking about a fairly static page, I tend to leave the ViewState on while developing, and begin selectively disabling it when the page works. That way, it's one less thing to worry about upfront. 

You may find this interesting, in ASP.NET 4.0, we will have more efficient control over disabling the ViewState: <http://www.asp.net/learn/whitepapers/aspnet40/#_Toc223325478>
I go one step further, I've created a class that inherits from the Page class and override 2 functions 

```
protected override void SavePageStateToPersistenceMedium(object viewState) 
{
}

protected override object LoadPageStateFromPersistenceMedium()
{
 return null;
}

```

Then have my page that requires the viewstate to be disabled inherit from this.
Works very well.