My company you get 10 days off per month on reserve. Technically you are allowed to move the days off, but only if reserve coverage is good...which it never is so effectively you are stuck with 5 on 3 off 6 on 2 off etc for the month. If you get super lucky you can move maybe 1 day off a month, but thats it. Even when you hold a line it is pretty much impossible to load you schedule up to the point where you will have more than 6 days off in a row. So at best you would spend 3 or more weeks at the crashpad and then get 12 or so days off and most lines aren't built with many days off on the front side of the month, so really you would only get closer to 8 or 10 days off in a row.

Most of the time your trips will start early and end late so you always have to commute in the day before your trip and commute out the day after your trip so days at home will be more like 6 to 8 a month.