With manual memory management you have to worry about the ownership convention of each chunk of code, with GC you have to worry about architecting strong/weak references so as not to inadvertently retain everything (not to mention latency issues), and with reference counting you have to worry about ownership cycles. In practice I haven't come up with a better strategy than enforcing some sort of top-down hierarchy which effectively smashes most of the differences in cognitive load between manual/refcounting/GC. GC has slightly less upfront busywork but in practice the tooling tends to be poor so it's a wash (if that). In GC and refcounting it's easy for one inexperienced/tired/sloppy individual to create a massive leak completely out of proportion to the footprint of their immediate code.
Pools, in contrast, allow the same top-down approach with the very significant benefits that I don't have to think about the hierarchy at a finer level than the pool itself (which I have to do for the 3 other approaches) and that memory management mistakes don't typically lead to the globally-connected-component of the dependency graph sticking around indefinitely.