What is a gender-neutral alternative to the expression "man-days"? I thought of "work-days" but am wondering if there might be another term. The use would be, for instance, "This project requires staffing of 1000 man-days over a six-month period."
Person-hour or person-day are gender-neutral alternatives suggested by Wikipedia.
Surely man hours or man days are both acceptable. You say you want a "gender neutral" alternative, but these forms are unmarked, much like we use mankind when talking about all people, not just those who are male. If you use a term like people days you might risk being ambiguous and waste time explaining your new word that could be spent on this massive project!
Days of effort is probably the most accurate. Work-days is shorter. Labour(or labor)days sounds more manual. Developer days is fine if you want to only look at part of the job, but Analysis days, Tester days etc would be needed too. I did wonder if Lady Days for the next hundred years would redress the balance (no, being 'humourous', or not). Man days does automatically make people think of the male first, so we do need something else, but it needs to clearly mean number of actual days of effort so people don't misinterpret as 'time to delivery'. It needs to be acceptable to feminists and misogynists alike. Work-days is what I'd vote for; I guess we'll see what gets into general use.
Since these development efforts are usually for comparison with other projects, Jira's idea of using points to indicate level of effort without saying directly it will take 5 days (and then being taken to task because it took 5.5 days) is a useful one, if people can be persuaded to use it properly.