That's a bit of a sliding scale. It's all about where you fall on the days you're on call. You can be relatively junior and working all the weekends, but if you're the most senior reserve working the weekends then you've got some buffer to not get abused every day. Conversely, if you've got some seniority to hold a Mon-Thur schedule, but you're the most junior person to do so, well, you're gonna get used. Overall the best general strategy seems to be a Mon-Thur schedule with some good buffer of people junior to you on those same days. I'd imagine that's probably around 50% category seniority in most NB categories. WB can really get screwy with the seasonal swings in flying and thus bidding patterns.