What is hosting? commonly, people will see hosting is a place for your design files to be put, so the larger files you have, you will need more hosting space. And in terms of bandwith, in simple way we can say it’s just like a road, where a road can have a traffic if it’s heavy. So does your website. More traffic on your site can cause your site hard to access and even down. Thus, you’ll need more bandwith as well.
In Siteground Hosting, at least it gives you 10GB space with 10,000 visits monthly which is more than enough for starter & medium site.