When you setup a website you will undoubtedly get a web hosting plan that includes not only a set amount of hard drive space for your pages, but also a budget of bandwidth that your site can utilize.  This number can be anything from 100 Megabytes (MB) per month to thousands of Gigabytes (GB) per month.  Often this vital statistic is ignored as people are looking forward to the problem of having too much traffic.  While most web sites that are created don't consume massive bandwidth, don't plan for your own failure by completely ignoring this factor when you sign up with a web hosting company.  At least ensure you get a reasonable amount of bandwidth based on what your site will be doing.  For instance if you are hosting home videos for a large group you may find that even 10 GB per month is not enough.  If on the other hand you have a modestly designed site that leverages background colors more than graphics you may find that 100 MB is more than enough even once you get the site to your desired user community.

The bottom line is to factor in all the relevant areas so you don't find yourself regretting your choices.