New ask Hacker News story: Ask HN: How important is it to have a mentor?

Ask HN: How important is it to have a mentor?
2 by 2bor-2n | 2 comments on Hacker News.
I never had a mentor during my years in the industry. So I am wondering is it really necessary to have a mentor for yourself as a developer/engineer? How much is it going to affect one's career in the absence of a mentor?