I've got this 10 year old rear projection television that I bought new. It has never had a service/cleaning. I have a service manual for it, and I was wondering if it is worth replacing the picture tubes to make it perform like it did when new, or if I should just do a dusting and cleaning.

The reason for the question is that when I do break into the set, it looks like the parts will involve 3 different tubes replacing at approximately 73.00 a piece. I haven't looked to see if I can find how many hours are on this set, but it has a lot. I find myself watching the plasma in the bedroom nowadays, and I'm just waiting on the funds for a projection system in the great room.