USB drives me nuts

["Michael Peters" <mp@mpeters.de>]

My Vista notebook has 3 USB ports. I currently use them for:  Soundcard,
Axon Midi controller, Steinberg key, Midi-2-USB, Nanokontrol, Nanokey 
(until
its usb plug broke off), Nanopad (probably I have forgotten one or two). I
use a passive little hub to plug them all in.

The thing that I wasn't aware of is that apparently it is important to plug
the devices exactly into the ports that were used during the installation.
Otherwise, often they aren't recognized. Today, I spent some time (not for
the first time) to persuade my system to recognize the Axon controller and
the Steinberg key again - each of them had been working before but not
today. This drives me nuts because I find it hard to understand the pattern
of this, much less the reason why this happens. My intuition believes all
devices should work everytime, independent where I plug them in.

Are there simple rules of thumb?

-Michael