The same units you use to refil and repair your units you can use to repair and refil your turretes. They do not autofix .
Actually, I believe they do .. I've watched this carefully trying to figure out how it works and this is what I've witnessed:
Ammo: Rearms only after firing it's last shot ... can actually be bad, since it will leave a turret with 1 ammo, when it may have 3 shots .. it shoots once, runs out of ammo, and rearms at the end of your turn .. *sigh*
But yeah .. it is automatic - if connected.
Damage: Yes, it will autorepair, I've watched my turrets repairing over time .. it's not fast, mind you .. can't remember if it's just 1 or 2 pts per turn .. but I do recall seeing it repair .. I'll have to re-check this, though .. got me curious to the exact number .. :)
yeah, just tested it ...
I damaged a gun turret, it healed 12 hits after the 2nd turn .. (1/2 life),
I also tried a mining station, but it only got 9 hits back (alot less than 1/2) .. so not sure the formula, but auto-heal .. definitely, yes. But it seems that it needs 1 round "peace and quiet" before it heals ...