diff --git a/pkg/metrics/gc.go b/pkg/metrics/gc.go
index 2457c0c6..9c00d872 100644
--- a/pkg/metrics/gc.go
+++ b/pkg/metrics/gc.go
@@ -1,7 +1,7 @@
 package metrics
 
 import (
-	"fmt"
+	"strconv"
 	"time"
 
 	"git.frostfs.info/TrueCloudLab/frostfs-observability/metrics"
@@ -64,7 +64,7 @@ func newGCMetrics() *gcMetrics {
 func (m *gcMetrics) AddRunDuration(shardID string, d time.Duration, success bool) {
 	m.runDuration.With(prometheus.Labels{
 		gcShardID: shardID,
-		gcSuccess: fmt.Sprintf("%v", success),
+		gcSuccess: strconv.FormatBool(success),
 	}).Add(d.Seconds())
 }
 
@@ -84,7 +84,7 @@ func (m *gcMetrics) AddDeletedCount(shardID string, deleted, failed uint64) {
 func (m *gcMetrics) AddExpiredObjectCollectionDuration(shardID string, d time.Duration, success bool, objectType string) {
 	m.expCollectDuration.With(prometheus.Labels{
 		gcShardID:    shardID,
-		gcSuccess:    fmt.Sprintf("%v", success),
+		gcSuccess:    strconv.FormatBool(success),
 		gcObjectType: objectType,
 	}).Add(d.Seconds())
 }
diff --git a/pkg/metrics/morphcache.go b/pkg/metrics/morphcache.go
index 7f6f2d7d..2440adcf 100644
--- a/pkg/metrics/morphcache.go
+++ b/pkg/metrics/morphcache.go
@@ -2,6 +2,7 @@ package metrics
 
 import (
 	"fmt"
+	"strconv"
 	"time"
 
 	"git.frostfs.info/TrueCloudLab/frostfs-observability/metrics"
@@ -46,7 +47,7 @@ func newMorphCacheMetrics() *morphCacheMetrics {
 func (m *morphCacheMetrics) AddNNSContractHashDuration(success bool, d time.Duration) {
 	m.nnsContractHashDuration.With(
 		prometheus.Labels{
-			mcSuccess: fmt.Sprintf("%v", success),
+			mcSuccess: strconv.FormatBool(success),
 		},
 	).Observe(float64(d))
 }
@@ -54,7 +55,7 @@ func (m *morphCacheMetrics) AddNNSContractHashDuration(success bool, d time.Dura
 func (m *morphCacheMetrics) AddGroupKeyDuration(success bool, d time.Duration) {
 	m.groupKeyDuration.With(
 		prometheus.Labels{
-			mcSuccess: fmt.Sprintf("%v", success),
+			mcSuccess: strconv.FormatBool(success),
 		},
 	).Observe(float64(d))
 }
@@ -62,7 +63,7 @@ func (m *morphCacheMetrics) AddGroupKeyDuration(success bool, d time.Duration) {
 func (m *morphCacheMetrics) AddTxHeightDuration(hash util.Uint256, success bool, d time.Duration) {
 	m.txHeightDuration.With(
 		prometheus.Labels{
-			mcSuccess: fmt.Sprintf("%v", success),
+			mcSuccess: strconv.FormatBool(success),
 		},
 	).Observe(float64(d))
 }
diff --git a/pkg/metrics/treeservice.go b/pkg/metrics/treeservice.go
index 48a450c7..ae24c41b 100644
--- a/pkg/metrics/treeservice.go
+++ b/pkg/metrics/treeservice.go
@@ -1,7 +1,7 @@
 package metrics
 
 import (
-	"fmt"
+	"strconv"
 	"time"
 
 	"git.frostfs.info/TrueCloudLab/frostfs-observability/metrics"
@@ -50,18 +50,18 @@ func newTreeServiceMetrics() *treeServiceMetrics {
 
 func (m *treeServiceMetrics) AddReplicateTaskDuration(d time.Duration, success bool) {
 	m.replicateTaskDuration.With(prometheus.Labels{
-		treeServiceLabelSuccess: fmt.Sprintf("%v", success),
+		treeServiceLabelSuccess: strconv.FormatBool(success),
 	}).Observe(d.Seconds())
 }
 
 func (m *treeServiceMetrics) AddReplicateWaitDuration(d time.Duration, success bool) {
 	m.replicateWaitDuration.With(prometheus.Labels{
-		treeServiceLabelSuccess: fmt.Sprintf("%v", success),
+		treeServiceLabelSuccess: strconv.FormatBool(success),
 	}).Observe(d.Seconds())
 }
 
 func (m *treeServiceMetrics) AddSyncDuration(d time.Duration, success bool) {
 	m.syncOpDuration.With(prometheus.Labels{
-		treeServiceLabelSuccess: fmt.Sprintf("%v", success),
+		treeServiceLabelSuccess: strconv.FormatBool(success),
 	}).Observe(d.Seconds())
 }
diff --git a/pkg/metrics/writecache.go b/pkg/metrics/writecache.go
index 67b9d8ca..b27e684d 100644
--- a/pkg/metrics/writecache.go
+++ b/pkg/metrics/writecache.go
@@ -2,6 +2,7 @@ package metrics
 
 import (
 	"fmt"
+	"strconv"
 	"sync"
 	"time"
 
@@ -148,7 +149,7 @@ func (m *writeCacheMetrics) SetMode(shardID string, mode string) {
 func (m *writeCacheMetrics) IncFlushCounter(shardID string, success bool, storageType string) {
 	m.flushCounter.With(prometheus.Labels{
 		wcShardID: shardID,
-		wcSuccess: fmt.Sprintf("%v", success),
+		wcSuccess: strconv.FormatBool(success),
 		wcStorage: storageType,
 	}).Inc()
 }
@@ -164,7 +165,7 @@ func setWriteCacheDuration(m *prometheus.HistogramVec, shardID string, success b
 	m.With(
 		prometheus.Labels{
 			wcShardID: shardID,
-			wcSuccess: fmt.Sprintf("%v", success),
+			wcSuccess: strconv.FormatBool(success),
 			wcStorage: storageType,
 		},
 	).Observe(d.Seconds())