Change Log Data Retention in CloudWatch Logs
By default, log data is stored in CloudWatch Logs indefinitely. However, you can configure how long to store log data in a log group. Any data older than the current retention setting is automatically deleted. You can change the log retention for each log group at any time.
To change the logs retention setting
Open the CloudWatch console at https://console.aws.amazon.com/cloudwatch/.
In the navigation pane, choose Logs.
For Expire Events After, choose the retention setting to change.
In the Edit Retention dialog box, for Retention, choose a log retention value, and then choose Ok.