Playing my first game with invaders turned on. I didn't flip them on until I had a decent level of technology, so I can manage them when they come, but the two wormholes in my space haven't spit anything out in a couple of years. I designed a mine-layer and accompanying cluster mines to help, but with nothing coming through, I feel like I'm wasting time and energy plopping down a new batch every time they shift.
So, the question: Do stable wormholes ever exhaust themselves? Are the two in my space essentially "empty?" Or will they always be a threat? Do they ever actually go away?