Is there any way to make units gain veterancy by using their abilities?
Example: medics gain lvls through healing.

Hmm, good question. If done only through the Data Editor, you may be able to use Behaviors as a counter that then triggers a requirement for the particular Veterancy. If you're fine using triggers, I'm sure there would be a way to track healing done by a Medic, and then use that to add the requirement for the Veterancy.

Post has been edited 1 time(s), last time on Aug 9 2011, 1:39 am by DevliN. Reason: Fixed typo.

Yup. As DevliN rightly points out.

You can create a Validator which 'Counts' the times an ability has been used. And once this validator returns true, it could unlock a Veterancy level (possibly through triggers).

If you have to resort to a triggered method, it might be simpler to create the entire system with triggers. Use Custom Values of units to track various abilities/statistics, and once they reach certain values - modify the experience that the unit has (and therefore it's current Veterancy level will change accordingly).