I think that we can forgo the commas in No. 1 below. Do you? I vote for No. 2. All examples below represent a single period of time/duration, so why split each of them with commas? Agreed? (1) a ten-year, two-month, three-day project (Not preferred.) (2) a ten-year two-month three-day project (Good!) I say no commas in any of the examples below. The project lasted ten years two months and three days. The project lasted ten years two months three days. a two-hour twenty-minute play (No hyphen after ‘hour’?) The play lasted two hours twenty minutes. (No comma after ‘hours’?) Thanks.