Tips to Extend Projector Lamp Life is a nice infographic from Project Lamps World that has some really good tips for helping you extend the lamp life of your computer projector. Most teachers now-a-days use a computer projector in their classroom (I think it is an essential tool for all classrooms). The projectors can go for $500-$3000 dollars with replacement lamps costing 30-50% of the original projector cost. Extending the life of your lamp is a very good thing to do.
I would also add another tip to this - do not wrap the video cable tightly and make sure it is not bent or stretched too much when being used. Many of the projector "failures" I deal with are actually issues with the video cable.