It depends upon your subject matter and length of your posts. If you are posting matter on same subject in some parts, then you may add it to your existing hub through your edit button. But, then, your hub will be counted as a single hub even if contains 10 posts or more. And one thing more. A hub with more than 1500 words may be too lengthy for viewers to read it at a single visit. So it may be better to create shorter hubs of around 1000 words to 1500 words with getty images than making a lengthy hub. It is upto you.