How do I heal land-armies?
So, my land (assault) armies are all damaged; how do I go about ‘repairing’ them, the way I would ships? Do I need to ship them home, or is the damage permanent, or will it just heal over time?
Solution 1:
They heal automatically, both when landed on a planet and while embarked.
(This has changed since the accepted answer was posted, they used to only heal when on a friendly planet.)
Solution 2:
Land them on an occupied or friendly planet. This will slowly heal each and every day they are not under attack.