And I like storing the time the prompt was printed so that I can keep track of how long a command took. When I care to keep track of when a command started, I just hit enter once or twice to get a “fresh” timestamp, then I have both an accurate start time and an accurate stop time. This is very handy if you run long jobs in a tmux session, for example.

If I rewrote the prompt each time I ran a command, I’d lose that record. (I suppose I could do the same trick in reverse and if I care to know how long a command will take, I could run it and hit enter a few times to queue up an empty command to create the same timestamp effect after the fact).