diff --git a/Neopixel_Goggles.ino b/Neopixel_Goggles.ino
--- a/Neopixel_Goggles.ino
+++ b/Neopixel_Goggles.ino
@@ -300,10 +300,16 @@ void setup() {
 
 void loop() {
   Rings.Update();
-  uint32_t t = millis();
-  if ((t - prev_time) >= MODE_CHANGE_TIME) {
+  /*
+   * We could store the return of the first millis call in a variable.
+   * But this routine is fast, so we only loose some milliseconds (if even)
+   * and we are not that time critical, that the MODE changes extacly after
+   * MODE_CHANGE_TIME. Calling millis twice, saves us 8 bytes, which is critical
+   * for the small storage space we have.
+   */
+  if ((millis() - prev_time) >= MODE_CHANGE_TIME) {
     mode = random(0, 9);
-    prev_time = t;
+    prev_time = millis();
   }
 }