If you have two copies of Gondor Bowman (
3R41) and want to use them both, you must exert a
![Gondor [Gondor]](https://lotrtcgdb.com/forums/Smileys/classic/gondor.png)
companion for each of them. So that means two exertions.
Similarly, if you have two copies of
They Are Coming (
1c196) you still have to discard three cards for each minion ("servant") you play from your discard pile. If you want to play two minions from your discard pile, you must discard 6 cards. So there is really nothing to be gained by having more than one copy of
They Are Coming in play.
The general rule here is that you can only use one special ability at a time, therefore you must pay the cost separately each time.
I hope that helps. By the way, what language do you speak?