That message is triggered by an hour counter, nothing else. I think it's possible that somehow it didn't get reset when you replaced your bulb last year because I wouldn't think that the warning would be displayed before 5,000 hours or so. It is hard to believe that you would rack up that many hours in a year.
Anyway, you're not going to do any damage to the TV. Continue using it until the lamp goes.
The key may be that it may only be turned on/off once per day. There has been some suspicion that you could get dramatically more hours with such a use pattern.
The number of on/off cycles definitely affect lamp life. In fact, if I know I'm going to step away from my TV for three hours or less, I leave it on rather than cycling it.
