diff --git a/src/asses/one.go b/src/asses/one.go
index d6b37d1..b1c6d5a 100644
--- a/src/asses/one.go
+++ b/src/asses/one.go
@@ -22,16 +22,25 @@ func One(ctx context.Context, p string) error {
 		return err
 	}
 
-	if threshold := 20 + time.Duration(rand.Int()%10)*24*time.Hour; time.Since(last.T) > threshold {
+   threshold := 20 + rand.Int()%10
+	if daysSince := int(time.Since(last.T).Hours()/24);  daysSince > threshold {
+      log.Printf("asses.One(%s) // no modified check as %vd since last check", shortp, daysSince)
 	} else if stat, err := os.Stat(p); err != nil {
 		return fmt.Errorf("cannot stat %s: %w", p, err)
 	} else if stat.ModTime() == last.Modified {
 		log.Printf("asses.One(%s) // unmodified since %v", shortp, last.T)
 		return nil
-	}
+	} else {
+		log.Printf("asses.One(%s) // modified (%v) is now %v", shortp, last.Modified, stat.ModTime())
+   }
 
 	if err := func() error {
 		if len(last.Cksum) > 0 {
+         if last.Modified.IsZero() {
+				log.Printf("asses.One(%s) // assume cksum unchanged given null modified ", shortp)
+				return nil
+         }
+
 			cksum, err := Cksum(ctx, p)
 			if err != nil {
 				return err
@@ -62,7 +71,7 @@ func One(ctx context.Context, p string) error {
 		return err
 	}
 	if err := checked(ctx, p, cksum, stat.ModTime()); err != nil {
-      log.Printf("failed to mark %s checked: %w", shortp, err)
+      log.Printf("failed to mark %s checked: %v", shortp, err)
       return err
    }