In the real world, they put up big reflective signs that tell you how fast you are allowed to go. In the digital world, no such signs exist. Like a top fuel dragster on a quarter-mile strip, the speed of the Internet is only limited by the equipment and techniques you use. Also just like the dragster, faster is better.
At best, a slow website frustrates your visitors and prevents them from trusting you. At worst, they leave before the page even loads. Website load times depend on a variety of factors, only some of which are under your control.
Don’t go super-budget when you decide who is going to host your website. I’m all for saving a buck, providing that you’re not sacrificing quality hosting to save a couple dollars a year. If just one potential customer doesn’t get frustrated with your slow website and ends up buying from you, then you’ll easily pay for the better hosting.
Make sure that the design of your website is current. Websites that use outdated technology only get slower with time, and will sometimes stop working completely if the technology becomes deprecated. Be wary of web designers that only offer a limited maintenance period, as web technology advances pretty quickly.
Another heavy hitter is the size of the images on your site. Doubling the image size in each direction actually quadruples the size on disk (and in transit), so that an image that might take a half a second to load now takes two seconds. Double the size again, and it’ll take eight seconds.
Bottom line: keep it speedy. Don’t lose your website’s visitors before they even see your website.