diff --git a/docs/adr/0005-cleaning-up-cache-strategy.md b/docs/adr/0005-cleaning-up-cache-strategy.md
new file mode 100644
index 000000000..14ba7e394
--- /dev/null
+++ b/docs/adr/0005-cleaning-up-cache-strategy.md
@@ -0,0 +1,22 @@
+# 5. Cleaning up cache strategy
+
+Date: 2022-04-27
+
+## Status
+
+Accepted
+
+## Context
+
+- Cleaning up the emails in cache which email have `receivedAt` was over 30 days from today
+- Cleaning up was triggered when user START the app on the first time of each day 
+
+## Decision
+
+- Cleaning up the emails in cache which email have `receivedAt` was over 10 days from today
+- Cleaning up was triggered when every time user START the app 
+
+## Consequences
+
+- Cache is clean up more usually 
+- Reduce the device's storage for the cache, may useful for user who have too many mails