How long before you meet the parents?

I met his mom 4 days after meeting him. It wasn't a big deal, really informal. We had to stop by her house to pick something up. She knew exactly who I was, it felt good to know he had been talking about me. My family lives 500 miles away, it will have been 4 months when he meets dad. He met my uncle and aunt after a month, he came over for a nice lunch. I think if it feels right, ya know? Then a month or so is fine, if it is short and very informal. The longer the amount of time you date, the more formal the meeting becomes. He will be meeting my dad at Thanksgiving dinner(my aunt invites strangers off the street to come, we are a very family family at holidays.) I don't know how it will be when he meets my mother. AlsO** the closer someone is to their family, the sooner they should be introducing them to their significant other, if that makes sense.