All headings — and headers include titles — should be in sentence case. Keeping things this way means that our readers will enjoy a consistent experience. But it also has several technical benefits.
Occasionally, we significantly restyle the wiki. We may go from headers that are styled upper-case to ones that are not. So even if you're seeing all upper case, remember that they aren't actually typed in upper case. They're just upper case as the result of a single line in our CSS. By keeping your headers in sentence case, we have the freedom to easily restyle the wiki.
Another thing to consider is sectional linking, which is case-sensitive. Editors should be able to count upon the fact that headers are in sentence case so that they can reliably link to sections.
Here are some examples:
|The quick brown fox jumped over a lazy dog||The Quick Brown Fox Jumped Over A Lazy Dog|
|A Noble encounter|
[correct because the "Noble" here is Donna Noble]
|A Noble Encounter|
|Will the real Dodo Chaplet please stand up?||Will the Real Dodo Chaplet Please Stand Up?|
|Behind the scenes||Behind the Scenes|