When to use HTML controls over ASP.NET controls?

hi,
Html controls are client-side controls and ASP.Net controls are server-side controls, and Every ASP.Net control contains one attribute i.e., runat = "server". means it tell us this is serverside control, runat server.

                                  Basically most of conditions we are using only ASP.Net controls, we need some static page in our website that conditions to we use HTML controls for Reducing The Burden of Server.
 
example if in our website we have any images,animations,etc that conditions to we use HTML controls because no need to execute these images and animations, these we placing display purpose only.

I think you understand my answer.

Thanks.