Always plan and budget just like you'll always make guarantee pay and that's it. If you make more, then shove that $ into savings. Don't be the typical airline person that owns fancy toys and once they can hold a line they have to pimp themselves out to pay for everything. The more you own, the more it owns you!

That being said, when I was on the 737, most of the time it was around 75-80 hours of pay per month. I don't know about 757 as I never flew that. On the 777, I bid long call reserve and fly as little as possible, so I NEVER break guarantee