Sometimes. It can definitely be normal if you’re tired, or stressed, or sick, or going to sleep, or on drugs. But sometimes it can be normal even without those things – see for example https://en.wikipedia.org/wiki/Hearing_Voices_Movement . I would be very concerned about any sudden change in hallucinations, but if you’ve had them for years and they’re not bothering you and you have no other symptoms of anything, I wouldn’t expect any disaster, though you can always go to a psychiatrist if you want to make them stop.
I’ve had full-blown audio-visual hallucinations* due to sleep deprivation. Good times.
And by “Good Times” I mean I do not recommend it at all – I am glad that I’ve had the experience, but I think it’s done permanent things to my sleeping patterns.
*They were mainly cases of confused processing – I’d be talking to somebody, then not notice that I’d closed my eyes because I’d keep seeing them. Then when I later opened my eyes again, they’d teleport to the location where my open eyes could actually see them.*