I use actualbudget.org to track all spending, but only update investment accounts ("off-budget" in Actual Budget terms) once a month. Completely deterministic, as all things related to numbers should be.

I have pointed my LLM at the SQLite DB and asked it to tell me what it could see from my last five years of transactions, and I was impressed with the things it picked up, and what it reminded me of, but I'm not sure I saw any value in the sense of anything I would change.

I'm going to have it review things monthly to see if that helps me, but I'm not sure it will. I'm generally already aware of how my finances are going because of my budget updates.