Fluorescent Lights: Troubleshooting and other questions

["Uriah"]

Someone told me that if you leave a burned out fluorescent bulbs in
their fixture with power applied you eventually damage the fixture.
Then if you put a bulb in it will burn it out in a second.
This seems to be true from my experience. Could someone explain why
this happens and how do you test a fixture to see if it is OK before
you place a new bulb in one and risk damaging the bulb.  
Thanks