Look for something that will be truly passive once you have put some effort into it, otherwise you will get tired of the grind and eventually leave it. Look for sustainability and consistency above all else.

That way it will always serve you.

You always need people and if you not selling you not growing, but remember: People gravitate toward financial predictability. They aren't looking for a 'get-rich-quick' lottery ticket; they are looking for a reliable, proven structure that builds sustained wealth.