When to use unbind?

When to use unbind?

Hi
If I understand correctly jquery tracks all event handlers registrations, and automatically unregisters them upon remove(), empty()  and the page ‘unload’ event.
Assuming I register event handlers for custom or system events *only* through the jQuery interface, when would there be any need to explicitly remove event handlers via 'unbind' (aside from within handler itself for single invocation purposes) ?

For example, I assume this would never leak on IE:

$(document).ready(function () {

      var _hold = ('#holder');

      $("#btnClick").click(function () {

      // _hold implicitly available via closure.
      // Anonymous handler creates cyclic reference chain: 
      // _hold references wrapped-set -> which references DOM div -> which references DOM input

            alert('clicked');

       });

 
// calling _hold.empty() or _hold.remove() or navigation to a different page breaks the cycle by removing the click handler, no need to call unbind.

 });

                          

       <div id="holder">

             <input id="btnClick" type="button" value="click" />

       </div>
 

 

Thanks

-Itai