diff --git a/Dockerfile b/Dockerfile
index 6450ecf..6fda926 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -19,4 +19,4 @@ HEALTHCHECK --interval=30s --timeout=3s --start-period=10s --retries=3 \
   CMD ["/endlessh", "-healthcheck"]
 USER nobody
 ENTRYPOINT  ["/endlessh"]
-CMD ["-logtostderr", "-v=1", "-enable_healthcheck"]
+CMD ["-logtostderr", "-v=1", "-healthcheck_enable"]
diff --git a/README.md b/README.md
index ec9907a..abd50a9 100644
--- a/README.md
+++ b/README.md
@@ -59,11 +59,13 @@ Usage of ./endlessh-go
   -geoip_supplier string
         Supplier to obtain Geohash of IPs. Possible values are "off", "ip-api", "max-mind-db" (default "off")
   -healthcheck
-        GET healthcheck_host:healthcheck_port/health and exit 1 if status is not ok or timeout is exceeded (for container healthcheck)
+        Perform healthcheck and exit. GET healthcheck_host:healthcheck_port/health and exit 1 if status is not ok or timeout is exceeded.
+  -healthcheck_enable
+        Enable healthcheck
   -healthcheck_host string
-        The address for container healthcheck (default "127.0.0.1")
+        The address for healthcheck. (default "127.0.0.1")
   -healthcheck_port string
-        HTTP port for container healthcheck; serves JSON with status and uptime at /health (default "51000")
+        HTTP port for healthcheck; Serves JSON with status and uptime at /health. (default "51000")
   -host string
         SSH listening address (default "0.0.0.0")
   -interval_ms int
@@ -129,7 +131,7 @@ You could also use an offline GeoIP database from [MaxMind](https://www.maxmind.
 
 ## Healthcheck
 
-The endlessh-go server exposes an HTTP health endpoint while the server is running. By default it listens on `127.0.0.1:51000` at `/health` and returns a JSON like this:
+The endlessh-go server exposes an HTTP health endpoint when the `-healthcheck_enable` flag is set. By default it listens on `127.0.0.1:51000` at `/health` and returns a JSON like this:
 
 ```json
 {
diff --git a/main.go b/main.go
index 9392536..a1d51a6 100644
--- a/main.go
+++ b/main.go
@@ -131,25 +131,34 @@ const defaultPort = "2222"
 var connPorts arrayStrings
 
 func main() {
+	// Core SSH server flags
+	connHost := flag.String("host", "0.0.0.0", "SSH listening address")
+	flag.Var(&connPorts, "port", fmt.Sprintf("SSH listening port. You may provide multiple -port flags to listen to multiple ports. (default %q)", defaultPort))
+	connType := flag.String("conn_type", "tcp", "Connection type. Possible values are tcp, tcp4, tcp6")
 	intervalMs := flag.Int("interval_ms", 1000, "Message millisecond delay")
 	bannerMaxLength := flag.Int64("line_length", 32, "Maximum banner line length")
 	maxClients := flag.Int64("max_clients", 4096, "Maximum number of clients")
-	connType := flag.String("conn_type", "tcp", "Connection type. Possible values are tcp, tcp4, tcp6")
-	connHost := flag.String("host", "0.0.0.0", "SSH listening address")
-	flag.Var(&connPorts, "port", fmt.Sprintf("SSH listening port. You may provide multiple -port flags to listen to multiple ports. (default %q)", defaultPort))
+
+	// PROXY protocol flags
+	proxyProtocolEnabled := flag.Bool("proxy_protocol_enabled", false, "Enable PROXY protocol support. This causes the server to expect PROXY protocol headers on incoming connections.")
+	proxyProtocolReadHeaderTimeout := flag.Int("proxy_protocol_read_header_timeout_ms", 200, "Timeout for reading the PROXY protocol header in milliseconds. If the connection does not send a valid PROXY protocol header in this time, the header is ignored.")
+
+	// Prometheus metrics flags
 	prometheusEnabled := flag.Bool("enable_prometheus", false, "Enable prometheus")
-	healthcheckEnabled := flag.Bool("enable_healthcheck", false, "Enable healthcheck")
 	prometheusHost := flag.String("prometheus_host", "0.0.0.0", "The address for prometheus")
 	prometheusPort := flag.String("prometheus_port", "2112", "The port for prometheus")
 	prometheusEntry := flag.String("prometheus_entry", "metrics", "Entry point for prometheus")
 	prometheusCleanUnseenSeconds := flag.Int("prometheus_clean_unseen_seconds", 0, "Remove series if the IP is not seen for the given time. Set to 0 to disable. (default 0)")
+
+	// GeoIP flags
 	geoipSupplier := flag.String("geoip_supplier", "off", "Supplier to obtain Geohash of IPs. Possible values are \"off\", \"ip-api\", \"max-mind-db\"")
 	maxMindDbFileName := flag.String("max_mind_db", "", "Path to the MaxMind DB file.")
-	proxyProtocolEnabled := flag.Bool("proxy_protocol_enabled", false, "Enable PROXY protocol support. This causes the server to expect PROXY protocol headers on incoming connections.")
-	proxyProtocolReadHeaderTimeout := flag.Int("proxy_protocol_read_header_timeout_ms", 200, "Timeout for reading the PROXY protocol header in milliseconds. If the connection does not send a valid PROXY protocol header in this time, the header is ignored.")
-	healthcheckHost := flag.String("healthcheck_host", health.DefaultHost, "The address for container healthcheck")
-	healthcheckPort := flag.String("healthcheck_port", health.DefaultPort, "HTTP port for container healthcheck; serves JSON with status and uptime at /health")
-	healthcheck := flag.Bool("healthcheck", false, "GET healthcheck_host:healthcheck_port/health and exit 1 if status is not ok or timeout is exceeded (for container healthcheck)")
+
+	// Healthcheck flags
+	healthcheckEnabled := flag.Bool("healthcheck_enable", false, "Enable healthcheck")
+	healthcheckHost := flag.String("healthcheck_host", health.DefaultHost, "The address for healthcheck.")
+	healthcheckPort := flag.String("healthcheck_port", health.DefaultPort, "HTTP port for healthcheck; Serves JSON with status and uptime at /health.")
+	healthcheck := flag.Bool("healthcheck", false, "Perform healthcheck and exit. GET healthcheck_host:healthcheck_port/health and exit 1 if status is not ok or timeout is exceeded.")
 
 	flag.Usage = func() {
 		fmt.Fprintf(flag.CommandLine.Output(), "Usage of %v \n", os.Args[0])
diff --git a/metrics/priority_queue_test.go b/metrics/priority_queue_test.go
new file mode 100644
index 0000000..74b189d
--- /dev/null
+++ b/metrics/priority_queue_test.go
@@ -0,0 +1,102 @@
+package metrics
+
+import (
+	"testing"
+	"time"
+)
+
+func TestUpdatablePriorityQueue_PushAndPop(t *testing.T) {
+	pq := NewUpdatablePriorityQueue()
+
+	now := time.Now()
+	pq.Update("item1", now.Add(2*time.Second))
+	pq.Update("item2", now.Add(1*time.Second))
+	pq.Update("item3", now.Add(3*time.Second))
+
+	if pq.pq.Len() != 3 {
+		t.Fatalf("Expected length 3, got %d", pq.pq.Len())
+	}
+
+	first := pq.Pop()
+	if first == nil {
+		t.Fatal("Pop returned nil")
+	}
+	if first.Key != "item2" {
+		t.Errorf("Expected first to be item2, got %s", first.Key)
+	}
+
+	second := pq.Pop()
+	if second.Key != "item1" {
+		t.Errorf("Expected second to be item1, got %s", second.Key)
+	}
+
+	third := pq.Pop()
+	if third.Key != "item3" {
+		t.Errorf("Expected third to be item3, got %s", third.Key)
+	}
+
+	if pq.Pop() != nil {
+		t.Error("Expected pop on empty pq to return nil")
+	}
+}
+
+func TestUpdatablePriorityQueue_UpdateExisting(t *testing.T) {
+	pq := NewUpdatablePriorityQueue()
+
+	now := time.Now()
+	pq.Update("item1", now.Add(2*time.Second))
+	pq.Update("item2", now.Add(3*time.Second))
+
+	// Update item2 to have an earlier time
+	pq.Update("item2", now.Add(1*time.Second))
+
+	first := pq.Peek()
+	if first == nil {
+		t.Fatal("Peek returned nil")
+	}
+	if first.Key != "item2" {
+		t.Errorf("Expected first to be item2 after update, got %s", first.Key)
+	}
+
+	popFirst := pq.Pop()
+	if popFirst.Key != "item2" {
+		t.Errorf("Expected popped first to be item2, got %s", popFirst.Key)
+	}
+
+	popSecond := pq.Pop()
+	if popSecond.Key != "item1" {
+		t.Errorf("Expected popped second to be item1, got %s", popSecond.Key)
+	}
+}
+
+func TestUpdatablePriorityQueue_UpdateToLater(t *testing.T) {
+	pq := NewUpdatablePriorityQueue()
+
+	now := time.Now()
+	pq.Update("item1", now.Add(1*time.Second))
+	pq.Update("item2", now.Add(2*time.Second))
+
+	// Update item1 to have a later time than item2
+	pq.Update("item1", now.Add(3*time.Second))
+
+	first := pq.Pop()
+	if first == nil || first.Key != "item2" {
+		t.Errorf("Expected first to be item2, got %v", first)
+	}
+
+	second := pq.Pop()
+	if second == nil || second.Key != "item1" {
+		t.Errorf("Expected second to be item1, got %v", second)
+	}
+}
+
+func TestUpdatablePriorityQueue_Empty(t *testing.T) {
+	pq := NewUpdatablePriorityQueue()
+
+	if pq.Peek() != nil {
+		t.Error("Expected Peek on empty pq to return nil")
+	}
+	if pq.Pop() != nil {
+		t.Error("Expected Pop on empty pq to return nil")
+	}
+}