In terms of bandwidth, the rule is the bigger the better. Which means that the higher the amount of bandwidth given to a subscriber, they can handle more traffic and faster.
How much is too much?
It's a lot better to have more than what is really needed to prevent the website from slowing down or being completely useless. But, if a website owner is really keen on doing the math on this one, the rule of thumb is that the web site designer or owner should multiply the kilobytes of data that will be uploaded per page to the number of pages that the website will have, and then multiply that with the number of views that one expects (or hopes) to have for that website. After arriving at the total of that calculation, a 10% to 20% buffer can be added, just in case.
Maximizing the Bandwidth
Since the bandwidth allotted to a subscriber cannot be extended without extra expense, what a website owner can do is compress the files that he or she will be uploading. There are a lot of software programs out there that produce tight HTML programming that will reduce graphics and image sizes, and these are best used for JPEG and GIF files.
There are also sites that will store or host photos and images which can be linked to the website, or tagged, or embedded. Some image hosting sites will let the images be stored for free, but there are others that would not. A website owner should ask which ones will allow linking before uploading the files. Otherwise it will be called bandwidth piracy and is illegal.
Another way to save some bandwidth space is the CSS or the Cascading Style Sheets which only attributes the values for any HTML element or command to the beginning of the command. There are web hosts that offer "unlimited bandwidth" if estimating the need of the website is a problem. Of course, there really is no such thing as "unlimited", but the numbers are so large it is almost impossible to surpass the limits anyway.
Protecting Against Bandwidth Theft
Thievery goes both ways, and a subscriber in turn would not want any one piggybacking on their bandwidth. It will slow down their sites and compromise functionality. The way to prevent bandwidth theft or piracy is through careful analysis of the search engines, logs and related sites. It is a tedious task and a thankless job that has to be done. The only way to get rid of links is to ask the other party to remove it or change the address of the image that they are linking to. The Internet is not a "public domain", and the owner of the site has the right to protect their intellectual properties.