Case in titles

Sentence case should be used for topic, section, figure, table and other titles.

It is possible to create titles for topics, figures and tables with letter case structures including the following:

Other variations are also possible, such as "all lower case except nouns".

For titles in publications, the following options are the most common:
Title case and sentence case afford the maximum re-use possibilities, because they can be easily transformed, in the processing stage, into:

You should use sentence case for all titles in DITA, other than publication titles. Sentence case is easier for an author to use, as it has simpler rules (first word and proper nouns must be initial capitalised).

The preceding applies to English, and may not be applicable in other languages (and writing systems) such as German, for example, where the first letter of all nouns is capitalised.