Do you automatically gain credits? Also corporal, no battles

[Goldy3]

I (stupidly) spend credits without attacking. (reinforcing a planet) so do you gain resources back or not? Also, I ranked up to corporal without even being in one battle.

[Hawkei]

A trap for young players. As soon as you rank up attacking will cost you an additional 100cr. So the bare minimum you should have is 300cr. 200cr to rank up and 100cr (or more) for the next battle. You will get credits over time, or for defending attacks, but other than this, you're screwed