Can objects be made to come and go?

I have been working on a rather ambitious animation and need to have objects come and go. I would prefer not break the scene and splice together different smaller animations. So far I have many objects moved off to the side, and some I have used a masking layer, but I zoom in and out a lot and it would be easier if could make them just appear and disappear. This would be like the little check box that turns off the layers, but that little check box does not seem to be a parameter that can be animated.

you can animate the amount parameter on the layers. Set it to 0 when it should dissapear. Use constant iterpolation.

Got it, I knew that had to be an easier way, Thanks!