In my TV lamp ( Henry AKA DimBulb knows what this is)  the lamp has done 1035 hours. Rather decent browing on both ends. There is no discernable end banding yet. This is run at least 12 hours a day 7 days a week.  The desk lamp at the radio station is left on 24/7 and I am guessing these Hungarian made lamps have been in at least a year. One bulb has a strong bit of browning on one end, the other ends lightly. This is a Chinese made fixture that had Hungarian Daylight lamps in it with European style color identification.  To get the lamps to start you have to preheat at least 30 seconds to get them to start. 

had a ge indonesia f15t8 in a server rack.been there several years 24/7.
dont know how much longer it would go as i sold the rack.