diff --git a/CHANGELOG.md b/CHANGELOG.md
index 420f74c..6f50623 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,10 @@ Please choose versions by [Semantic Versioning](http://semver.org/).
 * MINOR version when you add functionality in a backwards-compatible manner, and
 * PATCH version when you make backwards-compatible bug fixes.
 
+## Unreleased
+
+- fix: `memoryMonitor.LogMemoryUsage`, `logLevelSetter.Set` and `logLevelSetter.resetLogLevel` now use `libtime` instead of stdlib `time`, matching the convention `log_sampler-time.go` already documents ("uses github.com/bborbe/time for consistent time handling across the library"). All three drive time-threshold logic — log-if-interval-elapsed and auto-reset-after-duration — which could not be exercised deterministically against a frozen clock. The reset check uses `libtime.Now().Sub(lastSetTime)` rather than `time.Since(lastSetTime)`, so both the write and the read of `lastSetTime` come from the same clock.
+
 ## v1.6.20
 
 - update Go to 1.26.5 and update dependencies
diff --git a/log_memory-monitor.go b/log_memory-monitor.go
index 1c27f1d..597665f 100644
--- a/log_memory-monitor.go
+++ b/log_memory-monitor.go
@@ -10,6 +10,7 @@ import (
 	"sync"
 	"time"
 
+	libtime "github.com/bborbe/time"
 	"github.com/golang/glog"
 )
 
@@ -43,7 +44,7 @@ func (m *memoryMonitor) LogMemoryUsage(name string) {
 	m.mutex.Lock()
 	defer m.mutex.Unlock()
 
-	now := time.Now()
+	now := libtime.Now()
 
 	// Check if enough time has passed since last log
 	if m.lastLogTime.IsZero() || now.Sub(m.lastLogTime) >= m.logInterval {
diff --git a/log_set-loglevel-setter.go b/log_set-loglevel-setter.go
index 4b69352..2004752 100644
--- a/log_set-loglevel-setter.go
+++ b/log_set-loglevel-setter.go
@@ -11,6 +11,7 @@ import (
 	"sync"
 	"time"
 
+	libtime "github.com/bborbe/time"
 	"github.com/golang/glog"
 )
 
@@ -69,7 +70,7 @@ func (l *logLevelSetter) Set(ctx context.Context, logLevel glog.Level) error {
 	l.mux.Lock()
 	defer l.mux.Unlock()
 
-	l.lastSetTime = time.Now()
+	l.lastSetTime = libtime.Now()
 	l.currentLogLevel = logLevel
 
 	_ = flag.Set("v", strconv.Itoa(int(logLevel)))
@@ -90,7 +91,7 @@ func (l *logLevelSetter) resetLogLevel() {
 	l.mux.Lock()
 	defer l.mux.Unlock()
 
-	if time.Since(l.lastSetTime) <= l.autoResetDuration {
+	if libtime.Now().Sub(l.lastSetTime) <= l.autoResetDuration {
 		glog.V(l.defaultLoglevel).Infof("time since lastSet is too short => skip reset loglevel")
 		return
 	}