Veterancy is achieved by units as they destroy units in battle and use special abilities. Veterancy benefits units by decreasing their special ability (both offensive and defensive abilities) cool down timer, however the time it decreases varies according to unit. There are five ranks of veterancy, they vary in amount of experience a unit needs to gain to achieve the rank.
- Rank 5 (default): Single chevron. Standard special ability cool down time
- Rank 4: Two chevrons: Special ability cool down time reduced
- Rank 3: Single bar: Special ability cool down time reduced
- Rank 2: Two bars: Special ability cool down time reduced
- Rank 1: Gold star: Special ability cool down time reduced
Although the results vary, when a unit becomes rank 1 its special ability cooldown time is less than half that of the same unit which is rank 5. The cooldown time for the special ability typically is reduced by 2 - 5 seconds each rank. So keeping veteran units alive can very much help. Repair tanks can also gain veterancy from repairing other units, so a rank 1 Repair tank is much more useful than your standard rank 5 Repair tank. Other bonuses may result because of veterancy such as damage and armor but this is unconfirmed.