Many of wordpresss plugins requires you to edit the theme files and ask you to add lines like these -

<?php wp_related_posts(); ?>

(this cod is for wordpress related links plugin which I just installed by the way). Now the problem with putting such lines of php codes in theme files is that once when you disable the plugin or remove it, your blog will break as php parser will look for the function which is not there anymore.

The safe way of using wordpress plugin and more importantly while adding/editing theme files always use if statement like this -

<?php if ( function_exists('wp_related_posts') ) {
wp_related_posts(); } ?>

so first you are checking for whether the function exist or not and if the function exist, only then the function will be executed. So now even if you disable the function (i.e. plugin) the site won’t broke. Most of the time, the function name will be plugin name too.

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