I don't understand why, re flight planning, anyone has a problem.
i suspect it is "de riguer" for some of the longer sectors that airlines operate nowadays.
i was quite happy to do it on the BA DC10, and other airplanes, and we were mere amateurs in long sector operations compared to those these days.
It is about thinking which, if you read some of the posts on this thread, is severely lacking.
i suspect that the keyboard warriors (who seem to now lurk here) have not a clue about how airplanes operate.