You can tell when content is too long if people stop reading halfway or rarely comment. Online readers often scan instead of reading every line, so short and clear writing keeps them interested. If your message takes more than a few seconds to understand, it might be too heavy. Breaking text into short paragraphs or adding spaces helps. Try to make each post answer one main idea instead of covering everything at once. Watching your page analytics can also help you know where readers lose interest. When people like, share, or comment before the end, it shows the length is fine. Aim for simple, meaningful posts that respect your reader's time.