I am going to recruit some students as our class committee members, and I'm working on editing the new committee obligations now. For some of these duties, they only need to do it once during their term.

Can I describe these works as "Once at a time jobs"? I can not find any reference that explains the meaning and usage of "once at a time". So is it appropriate to use it here?

What do you native speakers normally describe the jobs that you only need to do it once in your lifetime or when you are on duity?

What's more, I used to watch a video clip of Mark Zuckerberg, and his wife said, "Mark, one thing at a time" at the end of the video. What's the meaning of one thing at a time in that video? Is it a warning to Mark that you could only let it happen once, otherwise he will be in trouble?

  • Piecemeal might be the word you need to look up.
    – Ricky
    Commented Jan 6, 2017 at 4:51
  • 'Once at a time' is a curious construction - I can't imagine when you might use it, ever! Possibly you are meaning 'one at a time'...?
    – Dan
    Commented Jun 27, 2017 at 10:27

2 Answers 2


I've never heard "once at a time" used. Instead you might see your idea expressed with more words, as in: "a duty he/she will need to perform once per shift", "once in each shift" or "once during each shift".

Either a "once-only" or a "one-time" requirement is the best I can come up with for referring to your lifetime as the time period. Otherwise you can use "(only/exactly/at least/at most) once per ______".

On the other hand...

"One thing at a time" means to focus on each thing separately, instead of trying to pay attention to many things in the same moment. It is usually meant to help lessen confusion or stress.

Also note that the phrase "once in a lifetime" usually refers to opportunities, not obligations, so it would be confusing if used here.


Once at a time jobs is incorrect.

The meaning of the idiom "one at a time" has already been explained on this site here (and the related phrase "for one thing" here)

The question about a word or phrase meaning something that just happens once was already answered on this site here (and the related question of a word for items which can only be used once here)

A quick review of this already answered question turns up phrases like:

  • a one-time event or one-time thing (more extreme would be once in a lifetime)
  • one-off
  • one-shot deal

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .