[xorcist]

That's a good reason to have timestamps in the history, which you should.

Something like

  export HISTFILESIZE=
  export HISTSIZE=
  export HISTTIMEFORMAT="[%F %T] "
  shopt -s histappend

really ought to be default in bash.

It's not as clear why you need it in the interactive prompt.

[hiAndrewQuinn]

I didn't make it quite as clear as I should: the reason to have it in the prompt is mostly so that you, or someone you're working with, can spot a trend you may not consciously think to look for if the timestamps weren't in front of you.

It sounds silly, but it has saved my butt more than once. Especially if you have bugs that e.g. only show up once per hour on the hour, and are otherwise fine.