I make a full-time living from my writing working part-time, but I'm very lucky. I live in New Zealand and our overheads are very low, we also have free health care. Also my husband has a stable job so we don't really rely on my income. If I have a low month, it's totally fine. Saying that, I haven't dropped below my minimum monthly earnings in over two years. I find the main key to this is 1. I've been doing this for 12 years. And 2. I always maintain multiple income sources. I expect jobs to dry up instantly (because they do) and always keep a back up ready to go.