I am using rust, but this applies to many other languages, I get warnings like, dead code, unused variables, and etc, and while I remove most of them, there are some im not sure of, I like running my program and there being 0 warnings, or 0 warnings as i scroll down my code, so for things im unsure of, i mark them so the compiler doesn’t put warnings there. I also add comments, starting with TODO:, it has some information about what to think about when i revisit it, also the todo’s gets highlighed in my IDE with my extension, but is this bad practice?
Fix the warnings first. By all experience, later is never.
First specs, then a (perhaps semi-formal) API description, then implementation, then first tests, then fix warnings, then rigorous tests, then fix all bugs before adding more features. It sounds contra-intuitive, but you go faster this way.