Nothing makes an ordinary moment heavier than realizing later it was the final one.

The last time something happens is almost never marked. An ordinary conversation, an ordinary visit, an ordinary evening becomes significant only in retrospect, and the weight it acquires is entirely to do with what came after. There is no way to identify these in advance. That is one of the genuinely hard parts of caring about people.

Rather than trying to spot them, be a little more present in the ordinary occasions with the people who matter. That is the only available response. It also happens to make the ordinary occasions better while they are happening.