Sometimes I will have the game volume on, and then other times I will have it off whilst listening to music in the background.
When I do have the game volume on though, I prefer to plug in my earphones into my switch for the full sound experience.
at the start when i played religiously, i played with my headphones plugged into the lite at all times. but the hourly music got repetitive much quicker than NL's for me and the rain sound is a little diluted so i now only play with my headphones for the first circuit around the island and then switch to watching videos as i play instead. if i'm pier fishing, need to catch a mole cricket or it's 5AM (best track) then the headphones go back in but that's it tbh.
I play with the volume on only when I want to hear stars flying in the sky LOL. Majority of the time, I play with it off and listen to some music that I can sing along to haha Whenever I had the volume on and played the game around people, they would tell me the game's music makes them sleepy and not gonna lie, it lowkey makes me feel sleepy too (the afternoon music anyways).
I usually listen on around mid volume and have something else playing along with it. There's not any urgent audio cues so I don't like the volume loud, and it's a little boring to have just the game audio unless i'm really focused on it.
I tend to have the volume off since I'm either listening to music or watching videos. I only tend to turn it up when I'm visiting and talking to my villagers since I like the noises they make. ❤
More often than not, I have the volume turned off and will be listening to something else online in the background whether it be YouTube videos, music, or a podcast. Sometimes I'll be chatting with friends while playing. I turn the volume on occasionally, for stuff like K.K. Slider performances for example, but yeah. Sometimes I'll play with the volume on the entire time, but it's not common. I was/am the same way with New Leaf, but with New Leaf I would at least turn the volume on the entire time when fishing because it was a fair bit easier to catch fish with the audio cue that the fish bit your line. With the rumble feature on the Switch Pro Controller, that's no longer necessary.