I feel the exact opposite regarding multiple visits haha. Horror Nights is normally a one night thing for me. I've spent nights at Knott's just sitting off to the side in scare zones and people watching. The pass they offer obviously makes that possible, but even long term mazes that were around like Trick or Treat were just fun to be in. I totally understand if you go to the event once a year, you end up knowing what to expect and that may make it a little less interesting. I think the one or two year gap probably makes it feel fresh in that sense.Definitely do it. I started doing every other year in 2012 after it got stale for me and it helped out my enjoyment of the event exponentially. Oddly, some mazes only last 2 years, so I never felt like I could be gone for too long. But even the repeats felt like old favorites after some time away. And it actually made me excited to go, when before it felt like a chore just knowing beforehand it would be awful. I used to LOVE KSF, but not as much as I love HHN now -- I could go to HHN multiple times a year and still enjoy it. Another huge factor for me was operations and service at KSF were always awful while HHN felt more organized. Even with the time away, crappy service at KSF didn't even bug me that much, or it genuinely has just gotten better, I can't tell.
What I will say in 100% agreement is the operations at Knott's is still far below what it should be. I think it's improved since the late 90's early 00's but for a theme park of their level it should be much better.