I'm in the "change it up" camp. My short fiction tends to have a choppy, highly sensory voice that is probably not to most readers' tastes (though people who like really literary fiction will enjoy it.) My longer fiction is intended to be more saleable, to make me more money (or that's the plan, anyway), so I want the voice to be more accessible and to take less of a central role. Hopefully one can still tell by my word choices and tropes that it's Libbie's fiction, but it's not as WOOooOOOoo VVVOOooIIIiiiCcey as my short stuff.
(in my short fiction, for example, writing "WOOooOOOoo VVVOOooIIIiiiCcey" might be totally acceptable, whereas I'd never try something so weird in the more commercial stuff.)
You can find a unique voice for every new thing you write. You can stick to one basic voice for everything, too, if that suits you. There's no rule here. And you can make lots of errors in any voice, as well. That's what revision is for.
Edited to add: I wanted to address the last part of your post, too. There was no "eureka" moment for me, except to realize that I'd been told over and over I should write in a very dry style with the simplest possible words and the least challenging tropes I could manage, so that everybody could enjoy my work. I was unhappy doing that -- I wanted to immerse myself (and the reader, I hope) in all my characters' senses, and create more memorable images than what was merely comfortable for the reader. So when I stopped giving a crap what other people thought of my writing (except for those I've asked to beta read and help me improve it), I found a voice I really liked. It's not going to be something every reader likes. It will turn a good deal of readers off, I imagine. But it's a voice I love to use, and that's what matters to me.
Am I still working on it? Of course! I'm still working on everything about my writing, and always will be. I'm never done learning this crazy crazy craft.