I set the line at "people" questions. I'll ask an LLM about math, programming, or how to better take care of my flowers. But turning to an AI for the human questions, relationship advice, I don't even understand why one would do that. The machine hasn't experienced that. There is no objective truth to these questions. Asking other people these questions lets you connect and bond.
I noticed a long time ago that each personality trends towards an average of the community they interact with - which makes me even more hesitant to use LLMs outside of work. I don't want to start talking like a clanker myself. I go out of my way to interact with weird people.
Thinking back to pre-LLM days, I would have the same line with classical search engines. I would never Google for relationship advice, since it doesn't know me well enough to actually say something worthwhile.