my lawyer's response about job change after received green card
"Unless you have a good reason to leave I would wait the 6 months. Generally, what USCIS looks at was did you intend to continue working for the employer once approved. So the exact amount of time is not always determinative. However, if you spend at least 6 months at the employer, they assume you had the intent to continue working for the employer. Could you get away with less time? Yes, but I would want to be able to explain it to USCIS should they ask."
How about the reason to leave is: no health insurance? good reason? Thanks