Sometimes you want it and sometimes you don’t. The sidebar, specifically here the one that appears to the side of content on your WordPress site (see on the right here), can be tricky customer when you don’t want it to appear throughout your site. On your posts pages you may want it with the categories, archives or meta widget inside. Some pages you may want it with a custom menu inside, and some you may not want it at all. So how do you achieve all that? Well, you’ll need to have a child theme set up (otherwise on your next update all your good work will be undone, arghhh!) and inside that you’ll want to create a new page template and have a copy of the default theme’s functions.php copied in.