Jquery best practice, checking for the existence of button/link before attaching an event
<p>I have a web page with buttons and links that may or may not exist.
I have jQuery that runs and assigns <code>click</code> events to these buttons and links.</p>

<p>Is it bad practice <em>not</em> to check for the existence of the buttons or links before I try to attach <code>click</code> or any other events? What are the repercussions?</p>

<p>If I should check for the button and link existence, what technique is best practice? 
Checking the length like so - <code>$('myButton').length != 0</code> or some other manner?</p>
