How do you define unnecessary work if this is... necessary for you? You are already benefiting from getting the tool/library/system for free, so you can still

How do you define unnecessary work if this is... necessary for you? You are already benefiting from getting the tool/library/system for free, so you can still compare writing the thing you need (necessary?) from scratch or adapting the FOSS solution — maintenance comes with both options. When you invest enough and are lucky, someone else might just fix the thing for you or pick it up and maintain it for you — but do not count on it, and you are good.