I think it will also depend on where you're at in your programming maturity. As a student, I had a fair grasp of programming concepts, so at my co-op, I had a mentor who would review my PRs, suggest his changes, and critique both his code and my code, which really felt like a game changer at the time even though it's such a small gesture. If I wasn't as comfortable with development then as I was, I don't think a mentor would've suited me at all.

Of course, this rides on you having the (RARE) opportunity of learning under a decent mentor