My experience in this regard comes from Java, not Ruby, but I think the basic concepts are the same: You are correct in that, for a lot of uses, ignoring abstra

My experience in this regard comes from Java, not Ruby, but I think the basic concepts are the same: You are correct in that, for a lot of uses, ignoring abstractions like GC is just fine. If you are building something that uses a lot of memory, requires high throughput or low latency, or are getting into situations where GC is taking up a decent chunk of your CPU time, then it can pay to have a better understanding of the GC concepts so you can make beneficial changes to your application or to the GC parameters. Plus, stuff like GC is kind of interesting by itself for some people. Some of my favorite sessions at JavaOne were always the GC and JVM internals ones, despite the fact that their immediate utility to me wasn't always obvious.