I used to always read everything, but I slowly started to see repeating themes. If a story is clearly different ill read it but most of the times i skip to the good part
I do skip some boring scenes without sex or i dont find anal to be that great so i will skip that too sometimes. Usually skipping content for me means its not a good game or there is so much grinding u get thrown out of story.
Really depends on the writing. Anything that goes on and on is usually not good. There should also be an exciting moment within the first few minutes, to introduce the game and establish that there is good payoff. The number one thing, in my opinion, that kills a VN with decent graphics is bad writing from authors who just don't know the makeup of a good story.
when the story just goes off on a tangent or drones on about a specific thing for way to long. but lets be honest, we play porn game to get to the sexy parts, not to read a novel.
I tend to skip when it's giving me backstory about a character i don't care/like, during masturbation sequences (male and female), and lesbian sex scenes. I'm probably one of the few guys in the world that doesn't get rock hard at a lesbian scene
There are only two situations in which I skip portions of a visual novel.
If I've seen this portion before, and I'm fairly certain I have a decent recollection of what happened in it, I'll generally skip. That's pretty much my MO for Such A Sharp Pain: I start over from the beginning, skip through all the bits I've seen, and keep a keen eye out for if there's something new near the front, instead of just additional scenes tacked onto the back. I do the same with pretty much all VNs I read/play.
The second reason I'll skip a game is if the narrative is boring me to tears and I can no longer stand to read the rubbish on screen. Characters talking in circles to pad out the dialogue; situations drawn out far longer than is necessary, reasonable or sane; long stretches of melodrama and cheap emotional beats to try and get me to feel something without the writing chops to actually succeed. There are other things that provoke this sort of reaction in me, but I don't want to harp on. If a game bores me, I'll skip through it until I find a section that seems interesting.
If a game turns me off entirely, I won't skip through it until I get to a portion I actually like. I'll just delete it.
I never skip anything. If the game is constantly boring/cringe/triggering/confusing (because of engrish or just poor writing), I'll just stop playing. I don't have enough time to play all the games I'd like to try, so no need to put myself through something I don't enjoy reading