Coffee: When it helps, when it hurts

Many peo­ple take caf­feine always, or never. But the ev­i­dence is clear: for some tasks, drink coffee—for oth­ers, don’t.
Use caf­feine for short-term perfor­mance on a fo­cused task (such as an exam).
Avoid caf­feine for tasks that re­quire broad cre­ativity and long-term learn­ing.
(Dis­claimer: The greater al­tert­ness, larger short-term mem­ory ca­pac­ity, and eased re­call might make the mem­o­ries you do make of higher qual­ity.)
At least, this is my take. But the is­sue is con­voluted enough that I’m un­sure. What do you think?