Yes, I use the correct word. Always remember about variable type. It is not always important because PHP uses type casting, but it may lead you to hard-to-find mistakes. For example, I need to get some variable value. There are only three allowed states: 0, basic, advanced. As you may see, 0 is easily recognizable as integer and two others are strings. If variable (it is post_meta to be exact) is not set, it should use default value – 0. So, it is pretty easy: $use = get_post_meta( $post_id, 'my_value_use', true ); if ( '' == $use ) { $use = 0; } I do not need to filter it…