I've been using Bootstrap for a while (specifically, version 3) and have noticed that I still am unsure whether I should always close columns with a that has a class of .row assigned to it after every 12 columns OR can I wait and apply that closing .row at the end of my code as long as I understand that any columns that add up to more than 12 columns in a single row will simply wrap automatically onto a new line. The benefit of the latter option is that it would be less code and less chances of forgetting to add that closing div tag for each 12 column row.
In other words, is it better to do this?
<div class="row">
<div class="col-md-8">
<p>some content here</p>
</div>
<div class="col-md-4">
<p>some content here too</p>
</div>
</div><!--/.row-->
<div class="row">
<div class="col-md-6">
<p>some content here</p>
</div>
<div class="col-md-6">
<p>some content here too</p>
</div>
</div><!--/.row-->
OR, is this method more efficient?
<div class="row">
<div class="col-md-8">
<p>some content here</p>
</div><!--/.col-md-8-->
<div class="col-md-4">
<p>some more content here</p>
</div><!--/.col-md-4-->
<div class="col-md-6">
<p>some content here</p>
</div>
<div class="col-md-6">
<p>some content here too</p>
</div>
</div><!--/one .row div to close them all-->