CloudWatch logs are all kept without deletion by default, however this can become costly over time so many administrators will configure a retention period. It is important to ensure that this is configured with a specific timeframe in accordance with regulatory requirements; the most common retention period recorded for compliance is 90 days. This can also be used in conjunction with the archive setting to rotate logs. For more information, see the AWS documentation.
References:
https://docs.aws.amazon.com/AmazonCloudWatch/latest/logs/WhatIsCloudWatchLogs.html
In AWS Console -
In Terraform -