So the first arc of Batgirl is over. How does DC tend to collect trades? I ask because I have way too many comics on my pull list so I need to start dropping them. I prefer to do that on an arc end so that I don't end up wasting money on the monthlies or miss issues when the trades come out. So I want to continue reading Batgirl (2011), I just can't do it monthly.
So far I've seen Scott Snyder's Batman for the past year in what looks like it's collecting a few arcs and Gotham City Sirens which seemed to collect approximately every five issues. Any advice?