Don't worry about your plasma dimming. By the time the plasma dims to any noticeable degree, you will have moved on to to another set, promise. The math on the half life of the plasma gas is like 15 to 20 years, they say. Plus, no bulb replacement during that time, whereas with DLP, the replacement bulbs (assuming your color wheel is still spinning) will cost more than the TV initially did.
The bottom line is that most of us will never watch our plasma until it dies because the gas runs out just like most of us will not have to buy another DLP bulb. Chances are, technology will be at a place where those replacement parts aren't worth the expenditure in the face of newer, better, bigger, crisper, more stable and longer lasting technology at a cheaper price.
