When a relationship starts everything seems like a milestone. First date, first kiss, first ... ahem ... sleepover. Then everything starts to get smaller and smaller, to where all you have is minutae.
For example, say you've been seeing a guy for two months and you're so proud that the two of you have made it to at least one phone call from each other each day.
That's a milestone.
Two months turn into to years, and in some cases you marry the guy. In other cases you have a knock-down-drag-out-wake-up-the-neighbors fight that ends with one of you moving out of your one-bedroom apartment at 11:30 p.m. on a weeknight.
In the case of the former, you end up talking on the phone a lot in very brief conversations, not unlike a pilot checking in with a controller.
When relationships are still fresh, they're more like "conversationships," meaning that when you talk to one another during the day you're still finding out new stuff. When relationships get down the road a bit it almost seems like you're talking in code.
"Hey sweetie! Thought I'd call and see what you're doing before your lunch break."
"Awww! That's so sweet! I'm finishing up a TPS Report before I head over to Schotzky's with my cubiclemate."
"That sounds so fascinating! Well, I hope your day shapes up. Blah, blah, blah. I love you!"
"I love you, too!"
"Hey babe, what's up?"
"'Bout to have lunch, you?"
"Nothing, applying for jobs."
"Sounds great. Gotta go. OKIloveyoubye."