Question

Is it good practice to check that element exist before remove it or it is not necessary ?
For example:

if(('#el').length > 0) {
  $('#el').remove();
}

is same as

$('#el').remove();

Answer 1

All jQuery selectors return a collection (perhaps empty) of jQuery objects and so if $('#el') (or more likely $('.class')) returned a number of objects remove() would remove them all. Likewise, if your selector doesn’t return any objects remove() will not remove any.

So no. It isn’t necessary.