For example, some hubs provide status lights for each port. Some hubs offer other features that aren't required, but that can be useful. If you are going to use the hub primarily on the move, such as with your PowerBook, a bus-powered hub might be a better choice (it will be smaller than a powered hub). Because some devices take their power from the USB interface, you should get a USB hub that is capable of providing its own power (many hubs can operate either on their own power or on power from the USB bus). Next, you should decide whether you want a self-powered or bus-powered hub. Having one or more extra ports above that number enables you to add other devices as you need them.

So you don't really need a USB port dedicated to every USB device you have?just those you want to always be available. There are many devices you will need to connect only periodically, such as a digital camera. Remember that USB is hot-swappable, meaning that you can connect and disconnect USB devices at any time.