I am adaptive to my partner, so it has differed with each. I tend to put myself in their shoes, empathize with their situation, and compromise with how much time their schedule/responsibilities allow for. (Which is not to say that I won't secretly harbor a desire for more, or less of their time.) I prefer to hear from them in some form daily, even if only a poke, but I can wait 3 days. After that I feel disconnected, and anxious. I will assume it's over, and start detaching rapidly if more than a week goes by with no communication, I'd say. I wish I was more patient, but I'm not. I fear abandonment, so I prepare to leave first.
If I am feeling busy or stressed I love to hear from them, but not to say much myself. I don't like to bog them down with my negativity, though I will open up if they are persistent, and/or wait me out.
If I really care about someone, and they give as much as they get, I will give them as much time as they want. I will find a way to fit them in. If I have a busy week, I will keep an entire weekend day open just for them. I want them to feel how important they are to me. I want to nourish the connection.
I am a curious person, and very interested in folks I admire & respect. I ask a lot of questions. I guess if I don't receive any questions in return I will assume they have lost interest, and it will make me sad. I need someone to share ideas with, and prefer they bring new & interesting information to the table. I was bored stiff in my marriage, because he didn't read, and we never had anything of interest to talk about. I get bored easily. My mind is like a sponge, and will seek new information elsewhere. I also love details. I want to know what they think and feel about everything under the sun.
Sounds exhausting, right? I am high energy in my areas of passion. When correctly stimulated I can stay up hours past exhaustion, and will give someone my undivided attention. I don't require excessive amounts of attention, but I do love it when I can get it.
I guess the main unrealistic requirement I harbor is wishing for consistency. If there is a flood of time, and attention in the beginning, and then a sharp decline, I take it personally, and feel very hurt. That's on me, though, and I need to get over it.