Heading tags should be used to structure a document by allowing a hierarchy of sub-sections. The correct use of Headings is to split a document up into relavent sections or paragraphs with a summarised heading.
Headings play a massive part in the accessibility of a web page. Screen readers (adaptive software) for blind and partially sighted people use them to jump to the different sections of a document so the page content can be assesed and the required information located quickly.
Heading structure example below:
This is my list of task and appointments for the week
.... and so on
In brief heading tags should be used in order. You shuold not have a