Hyphens, En Dashes, Em Dashes

Q. I’m writing an email to academics, selling a product offered “24/7, 365-days a year.” Should I write “24-hours a day, 365-days a year”? (The word year appears at the end of my sentence.) I am stumped with the slashes (/) and the hyphens. Thank you for your time and help!

A. You don’t need any hyphens, and it’s always nice to be consistent in your styling. So either “24/7, 365 days/year” or “24 hours a day, 365 days a year.” Hyphens come into play when you use a phrase like that to modify something else (our 365-days-a-year service) or when you use it in place of a noun (an eighty-four-year-old).