Changing Log Retention
By default, log data is stored indefinitely. However, you can configure how long you want 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/.
If necessary, change the region. From the navigation bar, select the region that meets your needs. For more information, see Regions and Endpoints in the Amazon Web Services General Reference.
In the navigation pane, choose Logs.
In the contents pane, for Expire Events After, select the retention setting to change.
In the Edit Retention dialog box, for New Retention, select the desired log retention, and then choose OK.