When using .find() the element list is overwritten, meaning if you have a cached basic object and you use .find() any subsequent calls to that cached object will be based on the results of that find, instead of the original element.
For example:
var element = $('.selector');
element.find('.child');
console.log(element);
After using find, the variable element will now contain the results of the .find() operation and not the original selector.