Data Transfer Limit
since as documented there are limitation on network traffic in M0/M2/M5 instances, it is mandatory to have a metrics/alerts (also for free ones) to monitor this value in a 7d sliding window
If you can provide the metrics saying x MB is used out of y GB provided (for both in and out) or x% utilized out of 100%, that will be helpful to the customers and keep a tab on the utilization.
We ran into problem where we have utilized 100% of data transfer provided and everything stopped working for us!!! It really took time for us to troubleshoot why suddenly things have stopped.
If you can provide this metric along with an alarm that you are hitting your max threshold of data transfer limit, it will be very helpful.