[skybrian]

I've never had to balance a tree either. But typically it's because the tree represents something essentially tree-shaped and preserving the structure is important. (For example, what would it mean to balance a DOM tree? Nobody would do that.)

On the other hand, I hope you're not saying that the DOM is the only tree you ever use and in 15 years you've never needed to build your own. If so, consider that companies might be interviewing people for programming jobs that aren't like that.