esc_attr on get_post_meta

Simple question,

I see that some themes are using esc_attr or esc_html and url after they define varible with get_post_meta, while others are using it during variable definition. What would be best practice

1.

$portf_icon = get_post_meta($post-ID,'dt_portf_icon',true);    
echo esc_html($portf_icon);

or

$portf_icon = esc_html(get_post_meta($post-ID,'dt_portf_icon',true));
echo $portf_icon;

Does it have any difference and which one would be best practices?