I talk to my SO daily; we live together so I can't really avoid it
On days when we might only see each other at bedtime and be too tired to talk, we email each other. I also have two roommates. One roommate is one of my best friends, so I talk to him every day he's home, and the other is my SO's brother, so we talk when we see each other (every couple of days). I talk to my mom every day to two days, and email my dad once a week. I talk to my best friends outside of my home a lot less--I just saw my best friend this weekend after not having seen her since July! We don't talk on the phone much, either, but I call her every now and again when I really need an ear to bend. She's used to it. Her boyfriend is another close friend of mine, and we instant message once a week or so to keep each other in the loop. Some of my friends, though, I can go months without talking to, but it doesn't seem to matter in the least; we're still happy to talk to one another when we see each other.