Malaysia Airline is changing the expiry of Enrich miles negatively and will apply this to all miles starting on January 1, 2015.
Currently miles expire at the end of third calendar year from when they were earned. The new policy is that they expire at the end of the month three years after they were earned.
Here’s example from Malaysia Airlines about the current and new expiry:
Here are the frequently asked questions by Malaysia Airlines about this change:
This is one of those “enhancements” that are negative. I have only credited flights to Malaysian’s Enrich program that would not have earned any miles on AA’s. If you are crediting miles towards Enrich, you should pay closer attention to the miles expiry.