Depends on who you fly for. FEDEX, UPS, ABX, ASTAR all have fairly stable schedules. You bid your trips and fly them. Things don't really change all that much. If you are flying for some of the other carriers things may be a bit more unstable. ABX doesn't get crew meals for most flights, but most are less than 4.5 hours.

Boxes don't complain about the turbulance, don't get sick, etc.

No regrests.