Generally headings split up paragraphs into related subtopics. It might be pointless to have a heading after every other paragraphs, however from SEO perspective it is to a great to have much number of headings on a page as could be allowed, particularly if they have the heading have keywords in them.
There are no specialized length limits for the contents of the <h1>, <h2>, <h3>, ... <hn> tag or labels yet an ability to think says that excessively long headings are awful for page to read. In this way, as with Urls, you have to be shrewd with the length of headings. An alternate issue you have to consider is the manner by which the heading will be shown. if it is Heading 1 (<h1>), commonly this would be in large font.
There are no specialized length limits for the contents of the <h1>, <h2>, <h3>, ... <hn> tag or labels yet an ability to think says that excessively long headings are awful for page to read. In this way, as with Urls, you have to be shrewd with the length of headings. An alternate issue you have to consider is the manner by which the heading will be shown. if it is Heading 1 (<h1>), commonly this would be in large font.