ASP.NET Tips #1 - Avoid running sites in debug mode

When it comes to ASP.NET, one of the most common performance blunders I see on a regular basis is accidentally or intentionally running sites in debug mode. Language-level optimizations, such as using StringBuilders, Arrays instead of Lists, Switch instead of If-Then-Else, and so on, are popular, but when you measure their real impact, they usually pale in comparison to optimizations at the framework level.

In web.config file:

<system.web>
   <compilation debug="false" />
</system.web>

in ASP.NET page (.aspx)

<%@ Page Debug="false" %>