Good luck going off of it.
I didn't wean. Just stopped. I didn't do it on purpose though. I just kept forgetting to take it. I'm terrible with taking meds, I always forget. That's why I'm on an IUD now, too, because I forget. Even a daily vitamin, I forget.
I didn't like it when I was on 1200 mg

Lithium wasn't too bad at 300 mg, but stopped working, then up to 600 mg still wasn't working, then they put me up at 1200 mg instead of 900. But it made me so thirsty and shakey. And since I was thirsty I always had to pee.