diff --git a/Router/item.py b/Router/item.py
index ec7f439..c12b7dc 100644
--- a/Router/item.py
+++ b/Router/item.py
@@ -61,6 +61,9 @@ def consume_item(request : Request, user_item_consume: UserItemConsume):
         return JSONResponse(status_code=HTTP_400_BAD_REQUEST, content={"message": "Item consume failed"})
     consume_history = ConsumeService.consume_history_db(user_item_consume)
     ConsumeService.purchase_history_save(consume_history)
+    expectation = ConsumeService.calculate_consume_expectation(user_item_consume.user_id, user_item_consume.item_name)
+    if expectation:
+        ConsumeService.set_consume_expectation(user_item_consume.user_id, user_item_consume.item_name, expectation)
     return JSONResponse(status_code=HTTP_200_OK, content={"message": "Item consumed successfully"})
 
 
diff --git a/Service/consume_service.py b/Service/consume_service.py
index 35cb073..65bd744 100644
--- a/Service/consume_service.py
+++ b/Service/consume_service.py
@@ -1,3 +1,4 @@
+from statistics import mean
 from typing import List
 from Data.item import *
 from Database.models import *
@@ -13,6 +14,31 @@ def purchase_history_save(data : ConsumeHistory):
             db.add(data)
             db.commit()
 
+    def calculate_consume_expectation(user_id: str, item_name: str):
+        with get_db() as db:
+            item_id = db.query(UserItem).filter(UserItem.user_id == user_id, UserItem.item_name == item_name).first().item_id
+            consume_histories = db.query(ConsumeHistory).filter(ConsumeHistory.item_id == item_id).order_by(ConsumeHistory.date).all()
+        if len(consume_histories) < 2:
+            return None
+        date_differences = []
+        for i in range(1, len(consume_histories)):
+            date_diff = (consume_histories[i].date - consume_histories[i-1].date).days
+            date_differences.append(date_diff)
+        
+        average_difference = round(mean(date_differences))
+        if average_difference < 1:
+            return 1
+        return average_difference
+    
+    def set_consume_expectation(user_id: str, item_name: str, expectation: int):
+        with get_db() as db:
+            item_id = db.query(UserItem).filter(UserItem.user_id == user_id, UserItem.item_name == item_name).first().item_id
+            user_item = db.query(UserItem).filter(UserItem.item_id == item_id).first()
+            user_item.consume_expectation = expectation
+            db.commit()
+
+
+
     def get_consume_histories_by_item_id(item_id: str):
         with get_db() as db:
             return db.query(ConsumeHistory).filter(ConsumeHistory.item_id == item_id).all()
\ No newline at end of file