I talk to my mom a few times a week, but sometimes I skip a week so I put once a week.
These are my in-laws though, which I refer to as my parents because I actually lived with them in high school, with my girlfriend who is now my wife (different rooms/beds). I haven't spoken to my biological father in about 8 years, and I only recently started talking to my birth mother. Funny this comes up because I just saw my biological father a couple of days ago when I was driving by the old house out of curiosity. I saw him and he saw me, and I kept on driving as he stared. Satisfying day indeed
As far as anyone is concerned, my in-laws are my parents. So I speak to them on average once a week