diff --git a/helpers.go b/helpers.go
index d3dbc2c..ff06820 100644
--- a/helpers.go
+++ b/helpers.go
@@ -1,4 +1,12 @@
 package main
 
-func ptrInt64(v int64) *int64    { return &v }
-func ptrString(v string) *string { return &v }
+import "time"
+
+var (
+	ptrInt64Zero   = ptrInt64(0)
+	ptrStringEmpty = ptrString("")
+)
+
+func ptrDuration(v time.Duration) *time.Duration { return &v }
+func ptrInt64(v int64) *int64                    { return &v }
+func ptrString(v string) *string                 { return &v }