Panasonic Lamp Life

We purchased this tv (Panasonic HDTV PT-40LC12) 4 years ago, with no knowledge of a 5000 hour lamp usage. But fortunately we also purchased a extended warranty, we have had to have the lamp replaced 4 times, now it is telling us it is time for our fifth one. Our warranty is now up and the new warranties out there will only replace lamps once. We never get 5000 hrs before they burst or tell us to replace. It is just my husband and I who live here and we both work, so the tv isn't on very often since we have one in our bedroom. Some days it isn't even used. I try to clean the air filter every time I dust, thinking that would extend the life of the lamp, but it doesn't seem to matter. From my research this is also one of the most expensive lamps out there. I really love this television, but when I go to replace it, I will research the lamp times and price better.