It's not unusual to use low-dose mood stabilizers if low-doses work for people. We should all only take as much medication as we need.
That said, I am usually on low-dose Depakote and I am a fan of it. Nothing else works as well for me. I increase it if/when I become hypomanic and happen to need more. For the most part, the lower dose keeps me stable.
My history is similar to yours. Earlier years were full of antidepressant trials.
Antidepressants either flipped me into hypomania or did not work for me.
A random assault gave me a traumatic brain injury. I'd needed an anti-epileptic drug to stabilize mood since. I became hypomanic/mixed/agitated -- chronically. Depakote is the one for me. I've been on it for three years straight now. I am a mess without it. I am calm with it.
Welcome to PC!

Hope to see you around the forums.

WC