I found this tip somewhere and thought I’d share this as the first in hopefully several posts of the “post a week ‘othon”.

To replace a layer in a composition with a new item from the project window select the layer to be replaced in the composition window. Press option and drag the item from the project window and drop it on top of the selected layer in the composition window. Simple.

This preserves everything you had done to the first layer. So this saves you the hassle from dropping in the new item, copying animation, effects and transforms.

I don’t know why I didn’t know before last week.