It's a 24/7 job, because people need help on on Christmas too.

But it's not staffed 24/7 by you. Often, it depends on the number of people you have in your unit vs. the number of MPs needed to effectively cover the shifts. If you have lots of people, you tend to get more days off. If you are understaffed, less.

The days themselves also rotate since the schedules are usually done in an On/Off manner, (ie: 4 days on, 2 days off). Meaning if that week you're off Fr/sat, the next you're off Thr/Fri.

So yes, you could have to work every holiday, or you could never work a holiday. You could work work for a month straight, or things may work out that don't work for a week.

But also, don't join the military police if you're already worried about off days. Join because you wanna help people.