Presumably you mean: "don't send requests [for new features] out of the blue"? I would add: if you do, don't expect the maintainer to merge it. Once it's merge

Presumably you mean: "don't send requests [for new features] out of the blue"? I would add: if you do, don't expect the maintainer to merge it. Once it's merged, it becomes their technical debt. Nonetheless, as a maintainer I always appreciate a pull-request, and as a developer I might fork/apply non-merged patches for projects where I needed that feature as well. In some cases, since they saved me a lot of time, I might fix their abandoned/closed patch and re-submit it upstream.