Hello, welcome to the forum and good luck for the long trip you begun!
This is my strategy to (1) decide to let the AI OCStation live or to take the planet and (2) hold an AI planet you didn't capture.
(1)
If the galaxy form a dead end of one or some planets isolated from AI territory by human territory, consider that this little "backwater" territory would hold:
- 3,000 Knowledge per planet
- 150,000 energy per planet
- some metal (20 x total-metal-deposit if harvesters are MkI)
- you would put economic stations that give energy and metal and eventually put advanced economic stations if you re-inject the Knowledge gathered here in them.
The AIP cost of such "economic territory" would be equal to 20 x number-of-planets.
Question is: would you pay that much AIP for that much economy? Are you short in energy? Are you hunger for more Knowledge? Are your rebuilds fast enough to handle AI reprisals? Is your economy beefy enough to afford the shiny new Starships you would unlock? And on the other hand, do you feel you have some headroom for taking some more AIP? If each wave is a pain and almost reach its goal each time, the answer may be "NO!" If the waves are a breeze and there is still datacenters out there, it's probably ok. Well, I won't teach you how to manage AIP here. (If you have trouble with AIP, tell us!)
On some situations, the answer to "would I take this planet" would be no. The planet is in the path of my territory expansion but it has 1 metal, I don't need K or energy, I'm short of AIP headroom, the the answer is "don't take this planet". Then how?
(2)
First of all: gateraid. The last thing you want is a wave warping in the middle of your territory.
Then, neuter: destroy all guards, all guard posts, deal with fortresses and Dire Guardian Lairs and other little nastinesses. You want the planet to contain ONLY the OCStation and the wormhole guardposts.
Well, if you let things as it, you'll still have some AI ships spawning in this planet. It won't cross terrifying thresholds, but still could be an annoyance if you regularly cross such planet. Often, I pay the 15 AIP to get either an economic boost (150,000 energy and 3,000 K) or to increase traveling speed with a logistic OCStation. But on very low AIP playstyle, it could be a strategy to just neuter path-planets.
Also know that you still can get 3,000K from such neutered planets with the hacker's covert knowledge extractor, at a little HaP expense, so the only things you don't get from this planet is the speed boost, the 150,000 energy and some metal. To save 15 AIP, it could be worth!
Then, there is the "Pumpkin" trick (Maybe one day I'll be as famous as Kahuna
)
Over-neutering Beachhead!
You know how to make a beachhead? You get a mobile builder in a planet with supply (adjacent to captured planet) and start to build things like if you captured the planet.
The core of the beachhead is a forcefield with Engineers, RRebuilders, eventually lightning/flak turrets, and the mobile builder. Then around this core you have all the turrets you'll put on a regular defense (see that famous Kahuna's guide
). Or you can just put snipers and long range missile turrets (remember to put some basic (needler, for example) turrets because Leech Starships are immune to both snipers and missiles).
Now, each time the AI will want to reinforce this planet, ships will spawn near the OCStation and get instantly took down by your turrets. The planet would stay permanently empty (unless they manage to take down some engi; you have to come back sometimes to see if it's still ok).
Little bonus: take the half of your sniper turrets and order them to attack the wormhole guardposts. They'll take some times, but at the end you'll have nothing more than the 15AIP OCStation. Why half? Because you need the other half to take down the spawning ships!
Remember this is only my advise. Some other players would have different opinions.
I hope this helped. If you still have some questions, we (I, at least) will be happy to answer.