Does firing a HQI MH bulb multiple times cause it to burn out faster

[johns]

I am runnign 250W Phoenix MH bulbs on HQI. I have a weird lighting schedule. I only run them 6 hours a day. And I divide the time they are on to 2 chunks of 3 hours, with a couple hours actinic 'down-time' in between. So the bulbs are fired twice a day, normally. I originally did this to reduce heat to the tank. Now I just do it for the 'why fix something that isn't broke' theory.

Anyway, I was just wondering if the extra bulb firing is going to cause them to color shift or burn out substantially sooner? Can someone explain what the actual bulb firing does to the bulb?

[Bluesop7]

Im not an expert by any means but the firing of the bulb puts stress on its internal components every time its fired. Although its not something to be worried about at all in the normal life of a bulb you might run into problems down the road from firing it twice as much as normal.