diff --git a/diagnostic_aggregator/src/aggregator.cpp b/diagnostic_aggregator/src/aggregator.cpp
index 69e382e57..5d6fd2339 100644
--- a/diagnostic_aggregator/src/aggregator.cpp
+++ b/diagnostic_aggregator/src/aggregator.cpp
@@ -84,12 +84,9 @@ void Aggregator::checkTimestamp(const diagnostic_msgs::DiagnosticArray::ConstPtr
       stamp_warn += ", ";
     stamp_warn += it->name;
   }
-  
-  if (!ros_warnings_.count(stamp_warn))
-  {
-    ROS_WARN("%s", stamp_warn.c_str());
-    ros_warnings_.insert(stamp_warn);
-  }
+
+  auto result = ros_warnings_.insert(stamp_warn);
+  ROS_WARN_COND(result.second, "%s", stamp_warn.c_str());
 }
 
 void Aggregator::diagCallback(const diagnostic_msgs::DiagnosticArray::ConstPtr& diag_msg)
diff --git a/diagnostic_aggregator/src/aggregator_node.cpp b/diagnostic_aggregator/src/aggregator_node.cpp
index f8c9d85fb..0ed239cbe 100644
--- a/diagnostic_aggregator/src/aggregator_node.cpp
+++ b/diagnostic_aggregator/src/aggregator_node.cpp
@@ -62,6 +62,5 @@ int main(int argc, char **argv)
   }
   
   exit(0);
-  return 0;
 }