My daughter, daily. She still lives at home (until she gets married, now looking like next year). My son once or twice a week on the phone, about half that often in person - I dote on my grandchildren.
My son and his wife live in another state and he owns his own business. He's 33 and shes 32. He's my only child and there are no grandchildren yet. I guess I want to know if I should reach out more. When I call a lot of times, I get voicemail and no return call so, I leave it alone. Sometimes, my daughter-in-law will reach out but my son does not. I just assume that he's busy and doing his life. When he and I do talk, it's like no time has passed. I'm just wondering if I'm not doing more.
Next time you speak to your son, let him know how you feel. It has to be aa two way street but if you don't tell him, he most likely thinks you're ok with infrequent contact.
They are my stepdaughters and they live nearby but they lead busy lives so now we see them infrequently perhaps a month or two goes by sometimes. Though I regularly watch one's infant son. Only a few good visits per year now including holidays when I host the extended family.
My oldest just moved out a couple of months ago, so it's still a bit early in the game for us, but I was making a point of trying to reach out at least once per week just to check in.
I have different relationships with my parents, probably more similar to what you have going on.
I just have one grown son. I talk to him about once a month ... but more often when we have things planned to do together. He's very busy and doesn't have a lot of time to chit chat. That's OK, I understand. I know if I need to talk to him .. I can at any time. I don't want to bug him.