People are constantly joining and leaving my team and requirements change on a daily basis and are vague/fuzzy. If an environment like this, I'm not sure formal

People are constantly joining and leaving my team and requirements change on a daily basis and are vague/fuzzy. If an environment like this, I'm not sure formal performance reviews even make sense. I get my shit done every week but whether it's good shit or not is very subjective. Whenever I get my performance review I will take it as a political statement.