diff --git a/pttodo/todo.go b/pttodo/todo.go
index 9eb3f57..bede663 100644
--- a/pttodo/todo.go
+++ b/pttodo/todo.go
@@ -1,8 +1,16 @@
 package pttodo
 
+import "time"
+
 type Todo struct {
 	Todo     string
 	Detail   string   `yaml:",omitempty"`
 	TS       TS       `yaml:",omitempty"`
 	Schedule Schedule `yaml:",omitempty"`
 }
+
+func (todo Todo) Triggered() bool {
+	last := todo.TS
+	next, err := todo.Schedule.Next(last.time())
+	return err == nil && time.Now().After(next)
+}