CloudWatch basic monitoring incurs a fee

Explanation

Many AWS services automatically send metrics to CloudWatch for free at a rate of 1 data point per metric per 5-minute interval. This is called basic monitoring, and it gives you visibility into your systems without any extra cost. For many applications, basic monitoring is adequate.

For applications running on EC2 instances, you can get more granularity by posting metrics every minute instead of every 5-minutes using a feature like detailed monitoring. Detailed monitoring incurs a fee.