Quote Originally Posted by bovi
Actually, they retain their experience, which makes it more or less an exploit since the AI doesn't do it. I always merge troops unless they're at more than 2/3 strength.
AI do retrain, although some very strange algoryth is used, so it do not do it always when it can. but even in rtw1.5 (not onlt BI or alex) AI retrains in some situations.
Seen this, and also seen full silver chevron AI troops many times.

Livius, if you are in a city that can train given unit you can also retrain. to do this you need to add this unit to "retrain" list, as it will not been done automaticaly