Yesterday in the evenings, I foolishly tried to trigger two reputation recalcs within a short time span and received the error message
Reputation cannot be recalculated more than once per day.
So I tried another recalc in the morning of the next day, only to receive the same error message again. I then found this answer about the recalc feature, stating "Note that you can only do this once every 24 hours" (which is more specific than "once per day"). And indeed, a few minutes after 24 hours had passed since my last successful recalc, I was allowed to trigger another recalc. Therefore, I suggest to change the error message to
Reputation cannot be recalculated more than once every 24 hours.
EDIT: How does "Reputation" work? was updated to include the "one recalculation every 24 hours" limit. The actual recalc error message, however, still reads "once per day".