Besides flexibility, making extra money on reserve (i.e. OG or PR) it’s not that easy. A whole lot of people will go first (MU, MO, etc) and even then OG or PR it’s 100% a scheduler option. Which I found it’s only on when you have < 2 hr show time or with crazy early or crazy late sign in. Only after a test run by the scheduler fails without using OG or PR.