Vader sounded old in rogue one.

Stewie from family guy still sounds like a baby to me.

Yeah. The voice stays young if you take care of it and are healthy. You can be 60 and sound like 30.

One of the few that probably goes against this is Julie Kavner, voice of Marge Simpsons. You can tell how different she sounds after 35+ years of doing Marge, Patty and Selma. I think it’s one of the reasons Marge seems to have less lines in more recent episodes.