Shortcut: trim layer to work area time / set in and out time of layer to in and out time of work area.
I spend so much time using the bracket keys to trim layers and most of the time I'm trimming to the work area boundaries. There should be a shortcut that does this automatically. When you duplicate a layer from another time or drop a new layer in a comp, just press a shortcut key to trim it to the work area. Simple but will save so much time manually trimming layers to the work area.