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: 
I tend to take the default of having it on when doing web.forms. 

But when writing my own user controls I disable it until I need it, or I find something doesn't work. I also monitor the size of the view state and when/if it gets too big I look at what the page is doing and change what I'm doing on the page. I.e. bind to data objects containing only the data that is needed and no more... stuff like that.
Turn off the ViewState by default by using a `<page>` element in the web.config. Using `EnableViewState="true"` in the `@Page` directive will no longer work once you disable the ViewState in the web.config. If you decide later that you need the ViewState for a specific page, you can turn it back on for just that page using a `<location>` element.

```
<configuration>
  <system.web>
    <pages enableViewState="false" />
  </system.web>

  <location path="MyFolder/MyPage.aspx">
    <system.web>
      <pages enableViewState="true" />
    </system.web>
  </location>
  <location path="Site.master">
    <system.web>
      <pages enableViewState="true" />
    </system.web>
  </location>
</configuration>

```

You need to do the same for any master pages that your ViewState enabled page uses.