There is zero point in practicing how to bleed. The only reason they run 24 hours per day is financial.
Until a few years back, the answer would have been ‘not at all’. Generally licence renewals were scheduled for start times from 6am to about 6pm. The late night sessions were mostly for conversion courses. The people on those would tend to get the same timing consistently, which did help with their sleep management. I recall doing most of my 767 and 747 conversion sims in the wee hours. When I moved to the 380, I was fairly early in the piece, so it wasn’t so busy, and the sim wasn’t running all night.
