Distance makes small updates carry some of the work ordinary presence once did.

Living near someone maintains a relationship without any content at all. You see how they look, what the kitchen is like, whether they are tired, and none of it has to be said. Distance removes all of that, and something has to take its place, which is why a picture of the sky or a line about a bus matters more than it appears to. Small updates are not chatter, they stand in for being seen.

Send the trivial thing you were about to decide was not worth sending. Frequency does more for a distant friendship than the occasional long and carefully composed message.