I don't live in Seattle and I don't use that many digital holds; for me most are just video games. But recently my county library added a limit for physical holds. "Wait times" seem to be one of those Goodhart's law metrics: by capping holds, you haven't really reduced wait times, just moved most of it out of sight of the reporting API.
But there's also kind of a mismatch of incentives at play here. As a patron, I really care more about throughput than latency on every hold I place. It takes me days or weeks to enjoy what I've checked out. But so does everyone else, so there usually isn't something I want on the shelves. In order to keep up throughput, I need something in my holds list ready when I return something. So I have a few dozen holds that go into the system as basically lottery tickets.
If it were just me, a policy of "unlimited holds, 2 out at a time" Netflix style would probably work, and I try to implement that by pausing (when I remember). As long I have an item or two out, I'd rather the librarians didn't consider my holds as any kind of "wait time" to optimize.
When a new book comes out the I know I want to read but do not wish to own for various reasons, I will generally put a hold on both physical and digital copies. Sometimes the audiobook too though that’s my least preferred way of consuming the content. Whichever comes available first is the one I will read. My library does have a holds limit but it is something like 75 items so I rarely have to think about it.
But there's also kind of a mismatch of incentives at play here. As a patron, I really care more about throughput than latency on every hold I place. It takes me days or weeks to enjoy what I've checked out. But so does everyone else, so there usually isn't something I want on the shelves. In order to keep up throughput, I need something in my holds list ready when I return something. So I have a few dozen holds that go into the system as basically lottery tickets.
If it were just me, a policy of "unlimited holds, 2 out at a time" Netflix style would probably work, and I try to implement that by pausing (when I remember). As long I have an item or two out, I'd rather the librarians didn't consider my holds as any kind of "wait time" to optimize.