If I'm making a person call, as rare as it is, and they don't pick up, I'll send a quick text explaining why I called and specify whether I need them to call me back, text me back or if no response is even necessary.

Thinking of times I've made a phone call it's usually due to needing to get some kind of info from someone that is necessary in the moment but meaningless in 5+ mins, so I call to liken the chances they'll see me reaching out. Example: I'm at the store and forgot exactly what X asked for. I'll call X, if they pick up they can tell me, if they don't I'll just go with my best instincts. But in 5 mins I'll already by out of the store and on my way home, so a response is meaningless at that point, so I'll follow up my call with a text saying as much.