The need for tutoring can only be determined on a case by case basis. At my school, our science record is very poor for the school's rank in the HSC due to the teaching method endorsed by our head teacher causing a significant portion of students to have tutoring whether it be one on one or small classes (eg Talent 100). I, personally, don't have tutoring for neither Physics nor Chemistry but I'm able to compete with the students that are tutored and for most of them, out-perform them. With that said, the way our assessments are set out cause most students to be poorly prepared and when I look at my peer's test papers, they often have inaccurate information - even students that are tutored and their responses shared on Moodle as "exemplars". Though, I do blame our school's teaching for that.
Bottom line is that, some students can benefit but it won't guarantee you good results. If good results don't prevail, it's not worth it.