Richard Taylor said:
what about the bonus that u get to send troops out of town to heal. how does that work?
Not exactly sure what you're asking, but ...
There is no bonus, and they don't get sent out of town.
There are healing troops event points, in most, but not all, events, the points for which you can see in the event details.
Heal a few million t6's and you will really help your team out in an event. Note though that most anything less than 10's of millions of points won't matter much in the result. Which is to say - don't spend time on this early on, for the resources expended there are better ways to spend it to grow. e.g. Buildings or Studies. OTOH, when you have t6 unlocked ... go nuts!
30% of troops are lost forever when they're lost - they go neither to Infirmary for Healing or Resurrection.
It is worth noting that, just like training, healing can be boosted and repeated. Whether you do so twice on 5k troops via 1 infirmary, or once on 10k troops via 2 infirmaries, same result. With the 1 infirmary, though, you'll have another building producing too, e.g. a House.
And if in the end you heal via gold (likely), you're just going to repeat healing anyways - higher troops, longer healing, greater impatience.
[Same argument for only 1 barracks - training t6 will take more than 1 day, and you will be in tomorrow to start the next one, so may as well only have one barracks.]
Infirmaries only matter if your troops are caught in town and you are unshielded. A situation happening less and less frequently, given the game changes.
Also note that things change over time. Accept that you will likely demolish many buildings and rebuild over time. (Just like endlessly redoing hero skills.)
Houses matter for Silver, which mostly only matters for studies. Maybe you fill up on Houses now, and Infirmaries later, or vice versa. High end studies cost > 1.5B each, and there are probably > 300 of those. Yet no point generating it until you need it. [One overslept shield and your silver will be gone!]
Depends upon how you play, and how your play evolves. e.g. Traps will want lots of infirmaries. Anything else, not so much.