Add user profile fields
I would make a single function, since all your functions do the same thing. It just needs an extra argument.

    /// one all-purpose function
    function saveData ($user_ID, $data_field) {
        $data = !empty($_POST[$data_field]) ? wc_clean($_POST[$data_field]) : '';
        update_user_meta( $user_ID, $data_field, $data );
    }

    /// define actions
    $actions=array("sfirst","slast",...);

    /// run actions
    foreach ($actions as $action) {
        add_action( 'woocommerce_save_account_details','saveData',$action);
    } unset($action);