Between the five of us organizers we have around 800 games. We always want to add to the library and our focus is in getting the top 500 games ranked on www.BoardGameGeek.com. Some of those, of course are wargames, so I've been tasked with getting those games. In addition, we look out for new games that may be hot right now. Though, those usually go on our Play and Win table. In addition we use our judgement if a hot game now will be around for a few years and thus should be in the library.
Because they go out of print and many don't return, it's important to keep an eye on things. My goal is to get the top 100 wargames. Beginning with those in the top 500 and then moving to the ones that interest me. And finally to the rest that will fill out the lists.
Anyway, here's a video of some of the acquisitions and one's I currently have. The other organizers have many as well.