I'm kind of curious; if I see a question with a title like this:
How to x y and z
Is making the title a question a valid reason for editing it?
People disagree drastically on what constitutes a "good enough" edit. Personally I say yes; we've had a user on the Unix and Linux SE that's been doing just that, and I'm a big fan:
The first thing the CHAOS team did when they started was go through the top 1000 questions on a bunch of sites and clean up their titles, specifically turning them into questions if they weren't, so clearly it's considered important
That depends. If the only thing your edit does is to make the title a question, don't bother. This gets debated now and then all over Stack Exchange; I'm firmly in the camp that holds that titles do not need and often should not be questions, because
On the other hand, if you're improving the title, and happen to make it a question, that's good. The key point is to improve; whether you turn a question into a non-question or a non-question into a question is irrelevant.
For example, the title edits that Michael Mrozek shows weren't just making titles into questions for the sake of it (the edit changelog message is misleading); they were generally (at least the ones I looked at) improving the title. For example, changing “an echo question” into “What does the syntax of these echo commands mean?” is a definite improvement. So is turning “Linux Serial port problem” into "How can I monitor serial port traffic?". On the other hand, I have a slight preference for “Monitoring serial port traffic” — not enough to bother to edit, but it's the title I'd pick if I was editing the post for another reason.
Some final notes, if you intend to go into an edit spree. Thank you, but…
If the title isn't actually a question, making it into one is a grammar improvement, and that on its own is a reason for editing it. But as waffles mentioned, it's a good indication that there might be other problems in the body of the question. So if I can, I try to improve the body as well, not just the title.
Yes. This is acceptable. As a basis for my answer, I provide you with Shog9's answer to a related question:
That's why editing is so crucial: read the whole question, distill its essence into a single sentence, and replace the title with that question. At worst, you've managed to improve one question; at best, you've shown them how they should ask future questions
Since he is now a Valued Associated I consider that a pretty definitive stamp of approval.