You must have some pretty good luck then John!
Shortly after we bought the coach, a couple of good friends gave us a 'Coach Warming" gift of replacing most of our original bulbs with Warm White bulbs. It made a huge difference in the harshness of the light. Of course, I couldn't bring myself to throw away all the other bulbs, so I basically have been rotating them throughout the coach, keeping the good Warm White bulbs where we use them most. The trend is certainly been the fixtures we use the most, so I really don't think there is anything strange going on...
Last week I finally had to buy a new set, so in 3 years we have went through 12 18 inch bulbs and 2 of the 12 inch ones. Granted we do use them a lot, and we are full-timers, so they are ALWAYS in use, but, I still find it strange for a florescent bulb to have such short life. I think our next step will be replacing the bulbs with LED strips. Not only are the bulbs getting pricey, they are inherently noisy (interfear with my HAM gear), they get fairly warm, and I think a few LEDS could go a long way in reducing power consumption also... But, the LED strips I have seen are not exactly "Cheap" either....
John