99% of the time I turn it off, mostly because I really dislike the sexual sounds, some games here and there I let just the music or ambient sound on, but never the sexual ones
I usually turn only the music off a put some chill lofi/low beat at the back. funny tho, i've been doing this with pretty much all porn/non-porn game since i was teenager.
At least running on Linux, Ren'Py is always far too loud out of the box. So moving all volume sliders far left is one of the first things I do with a new Ren'Py game.
I am inconsistent as to whether I turn sound off entirely. If there are AI voices or there is silly voicing with a few words and phrases they have little to do with what is said in the text, then I switch off the sound. Even if there is a separate volume slider for sound, I almost never use it. Otherwise I often keep the sound running at very low volume. Sometimes I use headphones, but usually I don't bother.
It's very rare that the sound files, let alone the background music, adds anything to the story or game.
Why some dev's do a reboot because of them thinking that some new music files will make a difference ... I really don't understand.
Not to mention those that think that the splash screen needs something that blasts your speakers out.