That was probably someone who picks trips.

Instead of bidding for the attributes of the trips you want, and don't want, you pick particular trips on particular days and create big groups that build specific lines. Works fine if you have the seniority to hold just trips. The problem is if you don't have the credit range you don't know if the lines you are trying to build are legal.

FWIW, I've never bid this way. I have bid groups that preference the type of line (commutable), the type of trips (no red-eyes and few days with more than two legs), and preferred layovers. Unless I have something special going on during the month, I don't have to modify my bid groups at all from month to month. I just copy them forward.