stand on (one's)/its own
To be able to function independently of other people or things; to have value independent of other related entities. Now that you're 18, you're expected to stand on your own and make good choices without your parents telling you what to do. I think the honors program is now capable of standing on its own, as it drew more applications than several other programs on campus. I think the sequel really stands on its own as a film—you don't need to see the first movie to appreciate it.