Toggle div based on checkbox value

.toggle() takes a boolean as well, like this:

$(function () {
  $('.always').change(function () {                
     $('#dates').toggle(!this.checked);
  }).change(); //ensure visible state matches initially
});

You can test it out here. I assume in the above you want the #dates hidden if .always is checked, that's what it'll do.

$('.always').change(function() {
 $('#dates').toggle(!this.checked);
});