At Beagle it is 72 hours for line holders. My line this month is 85 hours and I'll have about 5 hours of carry over from last month running into this month for about 90 hours of pay credit for this month.
Our reserve guarantee is 75 hours. When most people are first on reserve they want to fly as much as they can. This is the WRONG idea. You will want to work as LITTLE AS POSSIBLE so that you are getting paid for 75 hours but only work 40 (or even less if you are lucky). This way you are effectively increasing your hourly rate. About the only way I can see wanting to work as close to the 75 is if I was in a really ****ty crash pad or hotel and going insane sitting around in there.