Every pairing is different. We used to get a line build report from Alpa every month that detailed statistics for each base. Line purity (a pure pairing flies out of it's base exclusively) happens at each base, but some pairings will touch more than one base over the course of a typical 4 day. It is possible to have a full month of flying that never leaves your base and vice versa. In Houston, there are still plenty of trips in open time during the line improvement window that you can change up your schedule to fit your needs. Typically, every trip is going to be different.