If it’s my closest friend, I get back as soon as I possibly can. If it’s my wife, I get back as soon as I can, but I might take an extra bit of time to get something done first. If it’s my kids—as soon as possible. If it’s the inner circle of friends I will get back within at day or two usually, but sometimes I’ll wait until I see them next, unless my wife nags me to call them back.
If someone emails me, I am most likely to get back immediately, if it is an important email. If it is an announcement or something, or something impersonal, I’ll likely not pay it any attention. If it’s my parents I try to get back within a day.
I’m more likely to email or text back. I don’t like the phone except for about three people in the world. Anyone else, I’d do anything to avoid having to call them. I didn’t used to be like this, but I am now.
It generally has to do with how much I care about the person and how important they are (two different things) and what mode of communication they are using.