I have definitely heard the progress in my voice from when I started out to where I am now. My speaking voice changed a bit as well. I might do vocal strengthening, range exercises or breath control drills on days when I don't sing in rehearsal or performance.
Otherwise I do various basic warm-ups on the days that I do have rehearsal or a gig. It makes a huge difference in my opinion. But to each their own. I think being disciplined with regular exercises keeps vocal health in check and that's important to me.