diff --git a/functions.sh b/functions.sh
index a814179..3cd65ef 100644
--- a/functions.sh
+++ b/functions.sh
@@ -1,6 +1,8 @@
 # Linux Workspace Functions
 
-readonly time_ms='date +%s%3N'
+if [ -z "$time_ms" ]; then
+  readonly time_ms='date +%s%3N'
+fi
 
 function xlog() {
   if true_false "$LWS_DEBUG"; then